AU2009227553A1

AU2009227553A1 - A marker for an ore block and a method for tracking the travel of an ore block within a stream of particulate ore material travelling along an ore travel path

Info

Publication number: AU2009227553A1
Application number: AU2009227553A
Authority: AU
Inventors: David La Rosa; Walter Valery; Michael Wortley
Original assignee: Metso Minerals Australia Ltd
Current assignee: Metso Australia Pty Ltd
Priority date: 2007-04-05
Filing date: 2009-10-16
Publication date: 2009-11-05

Description

1 A MARKER FOR AN ORE BLOCK AND A METHOD FOR TRACKING THE TRAVEL OF AN ORE BLOCK WITHIN A STREAM OF PARTICULATE ORE MATERIAL TRAVELLING ALONG AN ORE TRAVEL PATH 5 FIELD OF THE INVENTION This invention relates to a marker for an ore block. This invention also extends to a method for tracking the travel of an ore block within a stream of particulate ore material travelling along an ore travel path. The invention also extends to a method of manufacturing a said ore block marker. The invention also extends to a system for tracking progression of 10 one or more ore blocks within a stream of particulate ore material traveling along an ore travel path. This invention relates particularly but not exclusively to a marker that can be used to track the progress of an ore block through a mineral processing plant including a set of conveyor belts, a crusher and a mill, and a method for tracking the progress of an ore block 15 through such a plant. It will therefore be convenient to hereinafter describe the invention with reference to this example application. However at the same time it is to be clearly understood that the invention could be equally applied to other applications that do not involve unit operations such as crushing and milling. Further the invention could be used to track the travel of a block of material within a stream of particulate material that is not an ore body 20 strictly speaking. For example it could be used to track the progress of particulate material in a quarrying operation. BACKGROUND TO THE INVENTION Mining operations are carried out on a large scale in many parts of the world. A mining 25 operation typically involves blasting an ore body within a host rock to break up the ore body and reduce it to a form in which it can be transported away from the blasting site. Subsequent to blasting, the particulate material is processed to separate the valuable mineral from the waste and host rock, e.g. to liberate the valuable mineral. To do this efficaciously the mean size of the particles in the particulate material is reduced in a series of unit operations. 30 Further the sizes of the different particles needs to be made more uniform to liberate the valuable ore. A rock body containing ore that has been blasted forms a pile of broken rock that is called a muckpile. This material is recovered from the blast site using a loading vehicle such as a front end loader. The front end loader then tips the broken rock material into a crusher. 35 The crusher acts to reduce the size of the broken rock material to a particulate ore material 2 having a certain maximum size. The particulate material from the crusher is then transferred by means of a first conveyor belt to an intermediate heap or stockpile. The particulate material is drawn in stages from the stockpile and deposited on a further conveyor belt which transfers it to a SAG mill. The size of the particulate material is reduced further and the sizes 5 of the different particles in the ore stream are made more even in the SAG mill. The mineral processing operations separate the valuable ore from the gangue material and thereby concentrate the valuable product for further processing. Very often an ore body that is being mined is not homogeneous and the ore body has regions of greater concentration of mineral, e.g. higher grade, than other regions that have 10 lesser grade. Further the minerals within an ore body can vary from one location to another. Prior to blasting mine engineers often have a reasonable three-dimensional geological map of the ore body they are about to blast. This is provided by geologists using techniques that model the ore body based on experimental data. These models produce reasonable maps of the boundaries of the ore blocks within the unbroken rock body. However an important point 15 to bear in mind is that these models map the boundaries of the ore blocks in the host rock that is still intact and has not yet been blasted. Many current mining practices assume that there is no movement of the ore boundaries as a result of blasting the rock body to break it up. However experimental work done by the Applicant shows that the rock does move very significantly as a result of the 20 blast. In fact Applicant has found that the rock body moves by several meters as a result of the blast and different regions or portions of the rock body move by different amounts. An inevitable result of this is that ore dilution is prone to occur. Ore dilution is when valuable ore is sent to the tailings dump and is thus not recovered as metal in the mining process. In addition this also leads to waste rock being directed to the processing plant for processing 25 with the ore. Clearly therefore it would be advantageous if a system or method could be devised to help measure the movement in different sections of a rock body as a result of blasting the rock. This would enable mining operators to adjust the three dimensional maps they have of the ore blocks within the unbroken host rock to take into account movement of the rock as a 30 result of blasting. This in turn would help to reduce dilution of complex ores due to this movement. In turn this should lead to improved volumes of valuable ore being produced by the processing plant and this in turn should lead to increased volumes of valuable metal being produced. Further with current mining practices many mines have no tools whatsoever to help 35 them determine when different blocks of ore within a large body of host rock are being 3 processed in a processing plant. Put another way there are no tools or techniques to track the progress of ore blocks as defined in the original geological map of the host rock through the different unit operations of a plant such as crushing and milling. As a general proposition the ore blocks are generally visually indistinguishable from 5 each other as they pass through the plant. While the material may be visible as it travels along a conveyor belt this in itself is not helpful. This situation is exacerbated by the fact that very often a mine will have an intermediate heap onto which particulate material is discharged in between the crusher and the SAG mill because an ore block may remain on the intermediate heap for days or weeks before it is processed further in the plant. Further the 10 order in which the ore is retrieved from the intermediate heap bears no relation to the order in which the different ore blocks were originally fed into the material processing plant. The intermediate heap therefore introduces another level of complexity into any effort to understand when different parcels or blocks of ore are being processed in say the SAG mill. This is sub-optimal, if not downright inefficient, as different ore blocks have different particle 15 breakage properties. It thus reduces the accuracy and/or quality of the simulation and/or control of the processing of the ore through the crusher and the mill, e.g. the SAG mill. Applicant is aware that a few mines may have well instrumented dispatch systems and these dispatch systems may help operators to predict when a certain ore body is being processed by the crusher and mills. However when ore blending is conducted at the site the 20 ore block sequence gleaned from the dispatch system is altered and this adds another dimension of complexity. Thus it is difficult to determine when a specific parcel or ore or a specific ore block is being processed. Clearly therefore it would be advantageous if a method and/or apparatus and/or system could be devised for tracking a block or parcel of ore from the mine site along the 25 conveyor belts to the crusher, through the crusher, through the further conveyor belts leading to the mills, and then through the mill. This would help to improve simulation and/or control of the operation of the mineral processing plant and this in turn would lead to better operation of the plants. In view of the increasing cost of energy there is a strong imperative to improve the efficiency and performance of mineral processing plants includingcrushers and mills. There is 30 also an economic imperative to maximize the recovery of valuable mineral from any given ore body and thereby maximize the monetary value of the product that is produced. SUMMARY OF THE INVENTION According to one aspect of this invention there is provided a method for tracking 35 the travel of an ore block within a stream of particulate ore material travelling along an ore 4 travel path during handling or processing of the particulate ore material, the method including: placing a plurality of transponders in or on the ore block that is either intact or broken, while it is stationary and prior to the handling and processing thereof, the 5 transponders being spaced apart from each other in or on the ore block; associating the transponders with the ore block in or on which they are placed; and detecting the passage of the transponders at one or more reader points along the ore travel path, thereby to track travel of the ore block within the stream of particulate ore material along the ore travel path. 10 The placing of the plurality of transponders may include placing at least some of the transponders in associated holes in the ore block. The holes may be arranged in a selected spatial relationship relative to each other. Placing the transponders in holes in the ore block may include placing the transponders in blast holes or stemming holes, prior to blasting the ore block. 15 The method may include allocating to each transponder an identification code and associating the identification code of each transponder with the ore block in which or on which it is placed. The method may further include allocating a unique ore block label to each ore block, and associating the identification codes of the transponders that are placed on the 20 ore block with the ore block label of the ore block on which or in which it is placed. The method may include allocating to each transponder a unique identification code (ID), and the method may include allocating a unique hole label to each hole in the ore block, and associating the unique identification code of the transponder with the unique hole label of the hole within which it is placed. 25 The method may further include identifying the initial position of placement of each transponder on the ore block and associating the initial position with the unique identification code of the transponder. The identifying of the initial position of placement of said each transponder may include using a Global Positioning Device (GPS) to indicate the initial ground position of 30 said each transponder, e.g. a handheld GPS. The method may include associating each transponder ID with an initial time stamp of information obtained by recording the date and/or time that each said transponder is placed in or on the ore block. The method may include entering or recording on a portable device one or more of 35 the following pieces of information: the ore block label, one or more of the hole labels, the 5 transponder IDs associated with the hole labels of the hole within which those particular transponders are placed, the initial location information associated with each of the transponders placed in or on the ore block, and an initial time-stamp of information that records when the transponders are placed on the ore block. 5 The method may include storing the entered or recorded information on the portable device in electronic format, e.g. for downloading later. The portable device may include a microprocessor module interfaced with a RFID reader, a GPS device, a data communication interface, e.g. a screen and keys, and an information database. Thus the GPS may be integrated with the portable device, e.g. 10 handheld device. The method may include correlating the ground position of each transponder with a model of the ore block within which it was placed. This may include correlating the position of each transponder with the block of ore and the boundaries of the block of ore within which it was placed. 15 The method may include downloading the stored information on the portable device from the portable device onto a computer system. The method may include identifying when the ore block travels past a reader zone along the ore travel path by using a transponder reader to read the unique identification codes of the transponders that travel past said reader zone along the ore travel path, and 20 from these identification codes determining the ore block that has travelled past the reader zone. The method may include locating a plurality of transponder readers at spaced intervals along the length of the ore travel path, and reading the unique identification codes of the transponders when they travel past a said reader zone and then sending the 25 unique identification codes of the transponders to the computer system for correlation with the ore block with which they were originally associated, whereby to track the travel of an ore block along the ore travel path. The method may include allocating to each transponder reader a unique reader label, and storing the unique reader labels of the transponder readers on a database that 30 is interfaced with the computer system, and the method may also include keeping a record of the transponder identification codes that are detected by the readers, and of the reader labels of the readers that detected the transponder identification codes. Further the method may also include generating a reader time-stamp each time a transponder is detected by a said reader.

6 The method may include presenting the information on the database selectively to the computer system, for a user to identify the last detection position of the ore block and the time when the ore block was detected. The method may include locating a transponder reader upstream of a unit 5 operation positioned at a point along the length of the ore travel path, so as to identify when an ore block enters the unit operation and is being processed in the unit operation. The method may include locating a transponder reader downstream of a unit operation positioned along the ore travel path, so as to identify when an ore block exits the unit operation. 10 The unit operation may include any one of the operations selected from the group of operations comprising: a crushing operation including a crusher, a stock-piling operation including an intermediate pile, and a conveying operation including a conveyor (belt), and a milling operation including a mill. The method may permit the transponders to be functionally destroyed in a unit 15 operation along the ore travel path, and the transponders may not be recovered and reused. Each transponder may be an RFID device, and each transponder reader may be an RFID reader. According to another aspect of this invention there is provided a marker for 20 placement on an ore block that is either intact or broken, for tracking the travel of the ore block along an ore travel path within a stream of particulate ore material, the marker including: a transponder; and a marker body defining an interior space within which the transponder is received, 25 the marker body having a robust outer wall for shielding the transponder from damage due to impact and collision with particulate material within the ore body travelling along the ore travel path. The transponder may be positioned within the interior space such that it is spaced inwardly away from the outer wall and a space or spacing may be defined between the 30 transponder and the outer wall. For example the transponder may be spaced away from the outer wall around its full circumferential extent. The spacing defined between the transponder and the outer wall may include a shock absorbing material, e.g. it may be filled with a shock absorbing material. In one form the spacing in the interior space between the transponder and the outer wall may be filled 35 with a shock absorbing material that is air.

7 The marker body may include at least one mounting formation in the interior space of the marker body, the mounting formation being for mounting the transponder within the interior space of the marker body spaced inwardly from the outer wall. The mounting formation may include an inner wall inside the interior of the marker 5 body, and the inner wall may be spaced from the outer wall thereby defining the spacing between the inner wall and outer wall. The inner wall may be a circular cylindrical inner wall extending concentrically between the two end walls, and the transponder may be received within the inner wall. The outer wall may be made of a resilient material, e.g. a synthetic plastics 10 material that permits some resilience. The marker body may be shaped and sized so that it moves with the ore block without significant segregation due to size. Further the marker body may have a specific gravity that corresponds broadly to the gross mean specific gravity of the ore material within which it travels along the ore travel path. 15 The outer wall may have a thickness of between 0.3 cm and 0.8 cm. The marker body may have a diameter of 3 to 10 cm, and a depth or height of 2 to 4 cm. The transponder may include a storage device, e.g. an electronic storage device, for storing unique identification information for that transponder. The transponder may be a radio frequency identification (RFID) tag, e.g. a passive RFID tag. 20 Further the marker body may be shaped and sized so that it encourages the marker to come to rest in a predetermined orientation. To achieve this object the outer wall may include opposed major end walls and a minor sidewall extending between the opposed major end walls, and the opposed major end walls may be sized and shaped to encourage the marker to come to rest with one of its major 25 walls resting on a support surface and the other major surface facing upwardly. For example the outer wall may be shaped and sized to form a close-ended shallow circular cylindrical body having said major end walls in the form of two opposed generally circular end walls, and the minor sidewall may be in the form of a shallow cylindrical sidewall extending between the end walls and the sidewall and merging with the end walls to form 30 rounded circumferential edges at their transition. The RFID tag may include a flattened RFID body having two opposed major surfaces and the direction of greatest flux of the RFID tag may be arranged to be orthogonal to the major surfaces of the RFID body. The RFID body is thereby mounted within the marker body with an orientation so that its direction of greatest flux is vertically extending when the marker 35 body orientates itself onto its major surface whereby to render the RFID tag susceptible of 8 being read by an RFID reader positioned above the ore body travelling along the ore travel path. The marker body may include two body parts that are attachable to each other to form the marker body. The two body parts may be attachable to each other by means of 5 complementary clip formations. Each body part may include a said mounting formation and the RFID tag may be clamped tightly between the two mounting formations on the two body parts when the two body parts are attached to each other. In this specification the terms reader, reading arrangement and detector and detecting 10 arrangement have been used interchangeably and shall be understood to refer to the same thing. According to another aspect of this invention there is provided a system for tracking progression of a body of ore blocks that travels along an ore travel path through a process, which system includes. 15 at least one marker having an onboard storage arrangement for storing unique identification information for the marker, each marker being for placement within the body of ore blocks that is to travel along the ore travel path through the process; an initial logging arrangement for logging information about an initial instance when the marker is placed with the body of ore blocks and for logging information about an initial 20 position of the body of ore blocks; at least one detecting arrangement placed along the ore travel path at a detection zone defining a detection position, each detecting arrangement being for detecting the at least one marker when it travels within the body of ore through the detection zone; a detection logging arrangement for logging information about a detected instance 25 when the at least one marker is detected by the detecting arrangement and for logging information about a detected position at which the marker is detected by the detecting arrangement; a presenting arrangement for extracting and presenting the logged information about the initial instance and the detected instance of the marker, and for presenting the logged 30 information about the initial position and the detected position of the marker, thereby to track the progression of the body of ore blocks that travels along the ore traveling path through the process. The marker may include a capsule having an interior, and the capsule may include a robust outer wall for shielding the onboard storage arrangement from the body of ore blocks 35 with which it travels along the ore travel path.

9 The detecting arrangement may include an interrogating arrangement for continuously interrogating the detection zone for detecting the at least one marker when it travels with the body of ore blocks through the detection zone. The marker may include an announcing arrangement for announcing the presence of 5 the marker within the detection zone when interrogated by the detecting arrangement as the marker travels with the body of ore through the detection zone. The announcing arrangement may include a transponder that is responsive to the interrogating arrangement, the transponder being in communication with the information storage arrangement for transmitting the unique identification information of the marker to the detecting arrangement in response to 10 interrogation from the interrogating arrangement. The transponder and storage arrangement may be a radio frequency identification (RFID) tag and the interrogating arrangement may include a RFID reader device. The at least one marker may in fact comprise a plurality of said markers, e.g. for placement within the body of ore blocks that is to travel along the ore travel path though the 15 mining process. Each marker may have an onboard storage arrangement for storing its unique identification information. Some of the plurality of markers may be placed within one type of body of ore blocks and others of the plurality of markers may be placed within another type of body of ore blocks. The system may include a computer apparatus having a computer database and a 20 computer network interfacing arrangement. Each detecting arrangement may include a terminal network interfacing arrangement for establishing communication over a wireless data communication network with the computer network interfacing arrangement. The initial logging arrangement may include a transportable detecting apparatus that is 25 transportable to a relevant marker for interrogating the relevant marker so that the relevant marker announces its unique identification information to the transportable detecting apparatus. The initial logging arrangement may include a geographic location determining apparatus for determining the position of the relative marker along the ore travel path. The transportable detecting apparatus may include a transportable database for 30 storing the identification information of the relevant marker and the geographic location of the relevant marker. The transportable detecting apparatus may include a time stamping arrangement for generating time and date information at the instant at which the transportable detecting apparatus receives the identification information from the relevant marker. The transportable 35 detecting apparatus populates the transportable database with the associated identification 10 information of the relevant marker, information about its determined position, and information about the generated time and date. The transportable detecting apparatus and the computer apparatus may include a data communication interfacing arrangement for downloading the initial information from the 5 transportable detecting apparatus to the computer apparatus, so that the computer apparatus populates the computer database with the downloaded initial information. Each detecting arrangement may be a stationary detecting arrangement and may include a terminal network interfacing arrangement for connection in communication over a wireless data communication network with the computer network interfacing arrangement. 10 The detection logging arrangement may include a stationary database at each stationary detecting arrangement. Each stationary database may be for storing the identification information of a maker that is detected when traveling with the body of ore through its associated detection zone. The computer data communication interfacing arrangement may be for downloading 15 the identification information from each stationary database to the computer apparatus, and for downloading a unique identification point address of the stationary detecting arrangement, so that the computer apparatus populates the computer database with the downloaded unique identification information of the marker that passed through the detecting zone and with the associated unique detecting arrangement address. 20 The stationary detecting arrangement may include a time stamping arrangement for generating time and date information at the instant at which the stationary detecting arrangement receives the identification information from the marker passing through its associated detection zone. The computer apparatus may populate the computer database with information of the address of each stationary detecting arrangement, the identification 25 information of the detected markers passing thought detection zone of each stationary detecting arrangement, and the generated time stamp for each marker. The computer apparatus may include the presenting arrangement for comparing the initial time stamp of each marker with its detected time stamps, and for comparing the initial position of each marker with its detected position, and for populating the computer database 30 for each marker with its compared information, thereby to determine the detecting points that the markers, and hence the body of ore blocks, have passed and the time that has elapsed until the markers passed the detecting points. The computer apparatus may include a user interface for presenting the populated information in the computer database to the user, and may also include a setup arrangement 35 for setting the stationary detecting arrangements and the associated locations and address 11 identification information of each stationary detecting arrangement on the computer database. The computer apparatus may include an internet network interface for remotely accessing the computer apparatus over the internet. According to another aspect of this invention there is provided a method for tracking 5 progression of a body of ore blocks that travels along an ore traveling path through a mining process, which method includes: placing at least one marker within the body of ore blocks that is to travel along the ore traveling path though the mining process, each marker having unique identification information stored in an onboard storage arrangement of the marker; 10 logging an initial instance and an initial position of the body of ore blocks with an initial logging arrangement; placing at least one detecting arrangement along the ore traveling path at a detection zone defining a detection position, and detecting the at least one marker when it travels with the body of ore through the detection zone; 15 logging the detection instance and the detection position when the at least one marker is detected by the detecting arrangement; and comparing the initial and the detection instances with each other, and comparing the initial position and the detection position with each other with a presenting arrangement, thereby to track the progression of the body of ore blocks that travels along the ore travel path 20 through the mining process. Placing at least one marker may include placing a capsule within the body of ore blocks, the capsule having an interior and an outer robust wall for shielding the onboard storage arrangement from the body of ore blocks with which it travels along the ore travel path. 25 The method may include continuously interrogating the detection zone with the detecting arrangement having an interrogating arrangement for detecting the at least one marker when it travels with the body of ore blocks through the detection zone. The method may also include providing the marker with an announcing arrangement for announcing the presence of the marker within the detection zone when interrogated by the detecting 30 arrangement as the marker travels with the body of ore through the detection zone. The announcing arrangement may include a transponder responsive to the interrogating arrangement, the transponder being in communication with the information storage arrangement, and the method may include transmitting the unique identification information to the detecting arrangement in response to interrogation from the interrogating arrangement.

12 The method may include providing the transponder and the storage arrangement onboard the marker by providing a marker with a radio frequency identification (RFID) tag inside the marker. The method may include providing the interrogating arrangement with a RFID reader device. 5 The method may include providing a plurality of said markers, each marker having an onboard storage arrangement for storing unique identification information, and the method may include placing a plurality of markers within the body of ore blocks that is to travel along the ore travel path though the mining process. The method may include placing some of the plurality of markers within one type of 10 body of ore blocks and placing some other markers within another type of body of ore blocks. The method may include providing a computer apparatus having an information database and a computer network interfacing arrangement. The method may also include providing each detecting arrangement with a terminal network interfacing arrangement and establishing a connection between the detecting arrangement and the computer network 15 interfacing arrangement over a wireless data communication network. The method may include providing the initial logging arrangement with a transportable detecting apparatus that is transportable to a relevant marker and interrogating the relevant marker so that the relevant marker announces its unique identification information to the transportable detecting apparatus, and providing the initial logging arrangement with a 20 geographic location determining apparatus and determining the initial position of the relevant marker along the ore travel path. The method may also include providing the transportable detecting apparatus with a transportable database and storing the identification information of the relevant marker and the geographic location of the relevant marker in the transportable database. The method 25 may also include providing the transportable detecting apparatus with a time stamping arrangement and generating time and date information at the instant at which the transportable detecting apparatus receives the identification information from the relevant marker. The method may include populating the transportable database with the associated 30 identification information of the relevant marker, including its determined position, and the generated time stamp. The method may include providing the transportable reader and the computer apparatus with a data communication interfacing arrangement and downloading the information form the transportable reader to the computer apparatus, and populating the 35 computer database with the downloaded initial information.

13 The method may include providing each detecting arrangement with a terminal network interfacing arrangement and establishing a connection between the computer network interfacing arrangement and each one of the terminal network interfacing arrangements over a wireless data communication network. 5 The method may include providing each detecting logging arrangement with a stationary database and storing in each stationary database the identification information of a maker that is detected when traveling with the body of ore through the detection zone of the detecting arrangement. The method may include downloading the identification information of each marker 10 from each stationary database to the computer, and downloading a unique identification point address of the detecting arrangement, and populating the computer database with the downloaded unique identification information of each marker passing through the detecting zone and with the associated unique detecting arrangement address. The method may also include providing the detecting arrangement with a time 15 stamping arrangement for generating time and date information at the instant at which the detecting arrangement receives the identification information from the marker passing through the detection zone. The method may also include populating the computer database with the associated identification information of each one of the detected markers, and information about the 20 position of the detecting arrangement, and the generated time stamp. The method may include providing the presenting arrangement with the computer apparatus and comparing for each marker its initial time stamp with its detected time stamp, and comparing for each marker its initial position with its detecting positions, and populating the computer database for each marker with the unique addresses of the detecting points that 25 it has passed and the time taken for the marker to pass between the detecting points. The method may include providing the computer apparatus with a user interface and presenting the information in the computer database to the user, and with a setup arrangement and setting the detecting arrangements and for storing the associated location and address identification information in the computer database. The method may further 30 include providing the computer apparatus with an internet network interface and remotely accessing the computer apparatus over the internet. The method may include placing at least one marker within a muck pile of ore blocks at a mine, and installing stationary detecting arrangements along an ore traveling path, and may include placing the stationary detecting arrangements at spaced intervals along a 35 conveyor system at a mine. The method may also include placing at least one marker within a 14 stockpile of ore blocks, and installing stationary detecting arrangements along a process plant ore traveling path, e.g. along a conveyor belt system at the process plant. The method may also include installing stationary detecting arrangements before a primary crusher plant section, before a secondary crusher plant section, and before an ore mill section. 5 According to another aspect of this invention there is provided an ore block marker for use with a system for monitoring progression of a body of ore blocks transported through a mining process, the ore block marker including: a marker body; and a transponder mounted or mountable within the marker body, 10 the marker body and the transponder when mounted within the marker body being for placement with the body of ore blocks and being detectable by the system as it passes thought the mining process along with the body of ore blocks, thereby to monitor progression of the body of ore blocks through the mining process. The marker body may include a robust outer sidewall defining an interior cavity within 15 which the transponder is mounted. The outer sidewall may define opposed major end walls and a minor sidewall extending between the end walls, and the outer wall may tend to come to rest on its major end walls, e.g. it may have a shape and a size that encourages this. The outer sidewall may be shaped and sized to form a close-ended shallow circular cylindrical body having major end walls in the form of two opposed generally circular end walls and a 20 shallow cylindrical sidewall extending between the end walls and merging with the end walls to form rounded circumferential edges at the transition. The edges of the body around the circumference of the major surfaces may be rounded. Thus the body may not have sharp edges where it transitions from the circular major surfaces to the cylindrical wall. 25 Thus the transponder may be mounted on the internal mounting within the interior space within the body. The transponder may be at least partially surrounded by air which assists in damping or attenuating blast energy that impacts the body before it reaches the transponder within the body. Thus the marker body may be shaped and sized so that when it is placed within a 30 body of ore blocks it moves with the body of ore blocks without significant segregation due to size. For example the marker may have a specific gravity correspond broadly to a gross mean specific gravity of the body of ore blocks within which it is to be pleased, in use. For example the tags may be arranged to have an SG in the range of 1.5-3.5, e.g. 2.0-3.0.

15 The circular cylindrical body may have a diameter of between 3 cm and 10 cm, e.g. a diameter of 5 cm to 8 cm, and a depth of between 2 cm and 4 cm. The housing should preferably be sized that when it is received within a body of particulate material it moves with the particulate material without significant segregation due to size. 5 The marker body may include at least one mounting formation in the interior of the marker body, the mounting formation being for mounting the transponder inside the interior of the marker body. The marker body may include an inner wall inside the interior of the marker body, the inner wall being spaced in from the outer wall, e.g. in a radial direction, so that a gap is 10 defined between the inner wall and outer wall. The inner wall may be a circular cylindrical inner wall extended concentrically between the two end walls, and the inner wall may define a cavity within which the transponder is mountable. The transponder may include a storage for storing identification information unique to the transponder, and the transponder may be capable of transmitting the identification 15 information to a receiver device forming part of the system. The transponder may be a radio frequency identification (RFID) tag and the RFID tag may be a passive RFID tag or an active RFID tag. By passive tag is meant that the tag does not contain its own energy source. Rather it is energized by a signal it receives from a reader. An active tag contains its own energy 20 supply and does not rely on receiving energy from a reader. The marker may include a body protecting material and the RFID tag may be embedded in the body protecting material. In particular the body protecting material may be shaped and sized to fit snugly inside the cavity defined by the inner wall. The body protecting material may have a shape in the form of a flattened cylindrical 25 body. That is the cylindrical body has two major surfaces of substantially circular configuration and a cylindrical wall of relatively short lineal extent. The body protecting material may have a diameter of 25-60mm and a depth or height of 10-20mm. The RFID tag may be mounted within the body with an orientation so that its area of 30 greatest flux is exposed to the reader when the marker body orientates itself onto its major surface. That is its area of greatest flux may be oriented parallel to the major surface of the body. To achieve this the RFID tag is orientated within the body so that its area of greatest flux is orientated in an upwardly facing direction. This positions the tag so that it has the best chance of being read by a tag reader when it passes the tag reader.

16 The marker body may include two body parts that are attachable to each other to form the marker body once the tag mounted on one of the body parts. The body parts may be attached to each other by means of complementary clip formations. Each body part may include a said mounting formation and the RFID tag may be 5 clamped tightly between the two mounting formations when the housing parts are attached to each other. The marker body may be formed from a synthetic material, e.g. a strong and robust synthetic material. In one form the body may be formed from NYLON TM filled with glass fibre. The outer wall of the marker body may have a thickness of between 3 and 8 mm. 10 The body parts may be formed by a molding operation. Conveniently the body parts may be formed from the same mold. The clips may be integrally formed with the body parts. According to another aspect of this invention there is provided a method of manufacturing an ore block marker for use with a system for monitoring progression of a body of ore blocks transported through a mining process, the method including: 15 forming a marker body having an interior; and mounting a transponder within the interior of the marker body, the marker body and the transponder when mounted within the marker body being for placement with the body of ore blocks and being detectable by the system as it passes thought the mining process along with the body of ore blocks. 20 Forming the marker body may include forming a robust outer sidewall for the marker body defining an interior cavity within which the transponder is mounted. The method may include shaping and sizing the outer sidewall so that it defines opposed major end walls and a minor sidewall extending between the end walls to encourage the marker to rest on its major end walls. The method may further include shaping and sizing the outer sidewall so that it 25 forms a close-ended shallow circular cylindrical body having two opposed generally circular end walls and a shallow cylindrical sidewall extending between the end walls and merging with the end walls to form rounded circumferential edges at the transition. The method may include shaping and sizing the marker body so that when it is placed within a body of ore blocks it moves with the body of ore blocks without significant segregation 30 due to size. The method may also include forming the marker so that it has a specific gravity corresponding broadly to a gross mean specific gravity of the body of ore blocks within which it is to be placed, in use, e.g. a specific gravity of between 1.5 and 3.0. The circular cylindrical body may be shaped and sized to have a diameter of between 3 cm and 10 cm. The method may also include forming the marker body so that it has a depth 35 of between 2 cm and 4 cm. The method may include forming at least one mounting formation 17 in the interior of the marker body, the mounting formation being for mounting the transponder inside the interior of the marker body. The method may include forming an inner wall inside the interior of the marker body, and spacing the inner wall inside the interior of the marker body away from the outer wall, so 5 that a gap is defined between the inner wall and outer wall. The method may include forming a circular cylindrical inner wall extending concentrically between the two end walls, the inner wall defining a cavity in which the transponder is mountable. The method may include providing a transponder having a storage for storing identification information unique to the transponder, and being capable of transmitting the 10 identification information to a receiver device forming part of the system. The transponder may be provided in the form of a radio frequency identification (RFID) tag, e.g. a passive RFID tag or an active RFID tag. The method may include embedding the RFID tag within a body of protective material, and shaping the body of protective material snugly to fit inside the cavity defined by the inner 15 wall. The method may include mounting the RFID tag within the body so that its area of greatest flux is exposed for the reader when the marker body orientates itself onto its major surface. Forming the marker body may include forming two body parts that are attachable to each other to form the marker body once the tag is mounted on one of the body parts. 20 Forming may also include forming complementary clip and clip receiver holes on the body parts, so that they are attachable to each other. The method may include forming mounting formations inside an interior of each body part, and mounting the RFID tag in position by clamping it tightly between the two mounting formations when the housing parts are attached to each other. 25 The method may include forming the marker body from a synthetic material, e.g. by a molding operation and with an outer wall having a thickness of between 3 and 8 mm. The method may include forming the clip formations integrally with the body parts with the same mold. According to another aspect of the invention there is provided an apparatus for 30 tracking the displacement of a block of ore on blasting and/or the movement of a block of ore through a plant, the apparatus comprising: at least one marker as described above according to any one of the preceding aspects of the invention; and at least one reader for reading the marker/s when they come within a reading range of 35 the reader.

18 The marker may include any one or more of the optional features of the marker described above in any one of the preceding aspects of the invention. The apparatus may include at least one reader that is a stationary reader. Each stationary reader may be positioned at a certain point along a path taken by the particulate 5 material and the reader reads the tags as they pass this point mixed up with the particulate material being treated in the plant. The stationary reader reads the identity of each tag that passes by and also records the time at which it reads the tag. The reader may comprise an antenna and the antenna may comprise a flattened antenna body having two major surfaces. The major surfaces may be arranged with a 10 horizontally extending orientation and thereby direct radio energy perpendicularly away from the major surfaces in a direction towards the path along which the marker moves. The major surface of the reader may be substantially parallel to the major surface of the tag to maximise the electromagnetic energy flux passing between the reader and tag. This increases the likelihood that the reader will read the tag when it passes in proximity 15 thereto, e.g. within radio wave range of the reader. The reader may read tags passing within a range of 0.25 to 5m of the reader provided that the orientation of the marker is horizontally extending as described above such as to maximize the flux passing between the antenna and the tag. The apparatus may also include a transportable reader, e.g. that is hand held and is 20 carried about by a user. The hand held reader may include an antenna and the hand held reader may also include a location identifier, e.g. a GPS based location reader. The transportable reader may be used to log the identity and the positions on the markers on the initial pile of broken rock material before the particulate material is discharged into the plant. The transportable reader may also be used to log the identity and position of 25 the markers across the rock body before it is blasted. According to another aspect of this invention there is provided a method of measuring movement of component portions of a three dimensional ore body through a mineral processing plant, the method comprising: placing a plurality of markers into different regions of a particulate material prior to it 30 being loaded onto a conveyor belt; logging the identity and location of each marker using a portable reader having location determining means; and reading the identity of each of the markers when they pass by each reader located at specific points along the path taken by material passing through the plant.

19 The method may include logging the time when each of the markers is read by the readers located at specific points along the path through the point. The method may include transferring the data collected by the hand held and stationary readers to a data collection means. 5 The method may include determining when different blocks of ore are being processed through different unit operations in the plant based on the information on the markers that is read by the readers and sent to the data collection means. The first step of placing above may include placing the markers onto the surface of a broken up body of rock that has been blasted in a mining operation. The markers may be 10 placed on the broken rock, e.g. the muck pile, at locations that are spaced apart from each other. The method may include reading the tags by means of readers located at two or more specific points along the path taken by material passing through the plant. The method may include reading the tags just downstream of a crusher. That is one reader may be located 15 downstream of a crusher, e.g. adjacent a crusher and downstream thereof but upstream of an intermediate heap. The method may also include reading the tags just upstream of a mill. That is another reader may be located upstream of a mill, such as adjacent to and upstream of a mill, e.g. downstream of an intermediate heap and upstream of the mill. Thus the markers can be read at two spaced locations along the length of the plant prior to the mill. 20 The method may also include a further step carried out prior to the other steps of placing the markers within the body of rock and logging their positions prior to blasting of the rock. Naturally this step would occur prior to the step of logging the position of the markers in the broken particulate material prior to blasting. Thus in some forms of the invention the markers are placed in explosives holes and 25 the position of these same markers is then logged after the blast on the muckpile and then the time when these markers pass through different portions on the plant is also logged. According to another aspect of this invention there is provided an apparatus or system for tracking the displacement of a block of ore on blasting and/or the movement of a block of ore through a plant including a crusher, a first conveyor, an intermediate heap, a second 30 conveyor, and a mill, the apparatus comprising: a plurality of markers as described above according to the first aspect of the invention for being positioned within the broken ore material in a plurality of different positions prior to it being placed on a conveyor belt; a hand held reader for reading the tags on the broken rock body and logging their 35 identification and their surface location; 20 a first stationary reader positioned above the first conveyor for reading the tags when they travel along the first conveyor and logging their identification and the time that they were read; a second stationary reader positioned above the second conveyor for reading the tags 5 when they travel along the second conveyor and logging their identification and the time that they were read; and a data collection means for collecting and organising the information on the markers read by the first and second readers. The markers may include any one or more of the optional features of the markers of 10 any one of the preceding aspects of the invention. The stationary readers may include any one or more of the features of the readers defined in the second aspect of the invention described above. The hand held reader may be carried about by a user and may include any one or more of the optional features of the hand held reader described in the second aspect of the invention. 15 According to another aspect of this invention there is provided a method of measuring the movement of boundaries of ore blocks within an ore body as a result of blasting, the method comprising: placing one or more markers including a transponder into an ore body at one or more locations prior to a blast; 20 logging the location of the marker/s prior to a blast by means of a reader that interacts with the marker; and logging the markers after the blast. The step of logging the markers after the blast may comprise logging the time at which the markers pass through the crusher and using the mine dispatch system to back calculate 25 where the tag was excavated from. Thus the markers indicate the position of certain parts of a rock body when it is still intact prior to a blast and also the location of these same parts after the blast. As such it helps to indicate the extent of the displacement of ore blocks and the like as a result of the blasting action. This method helps mine operators to reduce ore dilution which is when 30 valuable ore is lost and some waste rock is sent through the concentrator. Put another way it enables the displacement and translational movement of the various parts or blocks of the rock body as a result of the blast to be measured and taken into account. It is well recognized that such movement does take place and that it is different for different parts of the rock body.

21 The step of placing may include placing a plurality of markers into the ore body at spaced locations across the surface of the ore body. The step of placing may include placing at least some of the markers within holes drilled into the ore body from the surface thereof. The markers may be placed within holes in the ore body in which the explosives are placed, 5 e.g. blast stemming holes. The markers may be positioned a distance beneath the surface within these holes. The holes may be packed with a packing material after the explosives and markers have been placed in the holes. The construction of the markers as defined above in the first aspect of the invention has the effect that markers have a good chance, in excess of 50%, of surviving the blast when 10 placed in the same blast hole as the explosives. Thus while there will be some attrition of the markers it will not be sufficiently great to destroy the efficacy of the method using the markers for this purpose. The location/s of the markers may be logged with one or more hand held readers. Each hand held reader may be carried about by a user and may include any one or more of 15 the optional features of the hand held reader described in the second aspect of the invention. The invention also extends to a mineral processing apparatus including the apparatus defined above in the second aspect of the invention. The mineral processing apparatus may include a crusher and a mill and one or more conveyor belts. 20 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An ore block marker and a method and system for tracking progression of an ore block in a particulate ore stream traveling along an ore travel path using the ore block markers in accordance with this invention may manifest itself in a variety of forms. It will be convenient to hereinafter describe at least two embodiments of the invention in detail with reference to the 25 accompanying drawings. The purpose of providing this detailed description is to instruct persons having an interest in the subject matter of the invention how to carry the invention into practical effect. However it is to be clearly understood that the specific nature of this detailed description does not supersede the generality of the preceding broad description. In the drawings: 30 Fig. 1 is an upper three dimensional view of a marker in accordance with one embodiment of the invention; Fig. 2 is an exploded three dimensional view of the marker of Fig. 1 showing the structure of the marker body and also the transponder that is an RFID tag within the housing; Fig. 3 is a sectional front view of the marker of Fig. 1 showing the marker body and the 35 tag located within the housing; 22 Fig. 4 is a schematic drawing of components of an apparatus in accordance with the invention comprising the marker shown in Fig. 1 and a reader for reading the marker; Fig. 5 is a schematic drawing of an apparatus in accordance with the invention for carrying out a method in accordance with one embodiment of the invention; 5 Fig. 6 is a schematic sectional end elevation of the apparatus of Fig. 5 showing a reader positioned above a conveyor belt carrying a stream of particulate ore material with the markers being carried along with the stream of particulate ore material; Fig. 7 is an upper three dimensional view of a hand held reader for use with the apparatus of Fig. 5 in the method of the invention; 10 Fig. 8 is a schematic drawing showing an example of the information captured on a screen of a data collection means of the apparatus in Fig. 5; Fig. 9 is a three dimensional view of a marker being inserted into a blast hole prior to carrying out a blast; Fig. 10 is a schematic plan view showing the positions of an example set of markers 15 prior to a blast and also showing the positions of the same set of markers after the blast; Fig. 11 is a schematic flow sheet of an apparatus in accordance with another embodiment of the invention for tracking the passage of different ore blocks from a rock body through a mineral processing plant, up to the mill of the plant; Fig. 12 is a schematic front elevation of a conveyor belt showing a plurality of markers 20 along the length of the conveyor belt delineating various ore blocks within the ore body that is being processed; and Fig 13 is a functional block schematic diagram of a system, in accordance with the invention, for tracking the progression of one or more ore blocks within a particulate ore stream along an ore travel path. 25 In Figs. 1 to 3 a reference numeral 1 refers generally to a marker in accordance with one embodiment of the invention. The marker 1 comprises broadly a marker body 3 and a transponder that is a radio frequency identification tag (RFID tag) 5 that is received within the marker body 3. The marker body 3 is in the form of a housing having a flattened substantially 30 cylindrical shape. The housing includes a robust outer wall for shielding the tag from damage due to impact and collision with particles within the ore stream within which it is entrained. The outer wall has two major surfaces 7 and 9 that are circular. The cylindrical housing 3 is of short axial extent and thus the axial length of the outer wall extending between the two major surfaces 7 and 9 of the outer wall is short.

23 The housing 3 is made up of two interconnected housing parts 11 and 13. The two housing parts 11 and 13 can be connected to each other to form the closed housing 3 during the assembly of the marker 1 during the manufacturing process. The housing 3 including the outer wall thereof is made of a hard and strong synthetic 5 material, e.g. a plastics material, to enable it to have some chance of withstanding blast forces and also to enable it to be passed through a mineral processing plant up to a SAG mill with a reasonable prospect of not being damaged in the plant. Further the housing 3 has a wall thickness of about 3 to 8mm, e.g. of about 3 to 5mm. Again this wall thickness helps the marker 1 to withstand the forces described above. 10 The housing 3 is largely hollow and defines an interior space shown generally by numeral 15 which is filled with a shock absorbing material that is air. The purpose of the air is to absorb some of the force of a blast before it reaches the tag 5 thereby to help the tag to survive the force of the blast. The housing 3 also includes locating and mounting arrangement shown generally by 15 numeral 16 for locating and mounting the RFID tag 5 securely in position within the housing. The locating and mounting arrangement may comprise mounting formations shown generally by 16 on each of the housing parts 11 and 13. In the illustrated embodiment there is a mounting formation 16 on each housing part comprising a circumferential locator 21 for locating the RFID tag 5 centrally relative to the side 20 wall of the housing. There is also an axial locator 23 on the major surface of the housing part 11, 13 for locating the major surface of the RFID tag 5 spaced away from the associated major surface 7 or 9 of the housing part 11 or 13. In the embodiment shown in the drawings the circumferential locator 21 comprises a circular inner wall within which the RFID tag 5 is circumferentially received, e.g. snugly to 25 mount it centrally within the housing when it is viewed in plan view. In the illustrated embodiment the axial locator 23 comprises four outwardly projecting rib formations arranged in the form of a cruciform that each extend from the centre of the housing part to the circumferential locator or inner wall 21. The rib formations are equally spaced apart and thus are spaced about ninety degrees apart from each other. The rib 30 formations do not extend up away from the associated major surface of the housing part as high as the wall 21. Thus the wall 21 and rib formations 23 form a secure and stable mounting within which the tag 5 is snugly received. The locators 21 and 23 are designed to hold the tag 5 securely while still providing as much air space for blast attenuation between the major surfaces and side wall of the housing part as possible.

24 Each housing part 11, 13 has a pair of positive clip formations 25 for engaging passive clip formations 27 on the other housing part 11, 13 to attach the housing parts 11, 13 to each other during assembly. In the illustrated embodiment each housing part 11, 13 has two positive clip formations 25 that project out away from the wall of the circumferential locator 21 5 and are diametrically opposed from each other around the wall. Further each housing part 11, 13 has two passive clip formations 27 that are basically openings in the wall thereof for receiving a positive clip formation 25 from the other housing part 11, 13 therein. Further it should be noted that each of the housing parts 11, 13 is basically the same. 10 Thus each housing part has the same circumferential locator 21 and axial locator 23 and the same clip formations 25 and 27. This is clearly not essential but simplifies manufacture of the housing parts 11, 13. The RFID tag 5 has a flattened circular cylindrical configuration having two major surfaces 29, 31 as shown in the drawings. Its orientation mimics that of the housing parts 11, 15 13 with its major surfaces 29, 31 extending parallel to the major surfaces of the housing parts 11, 13. Further the tag 5 is received substantially centrally within the housing 3 when viewed in plan view within the inner wall 21 with its circumferential wall spaced radially in from the wall of the housing part 11, 13. Further the tag 5 is positioned substantially midway along the length of the side wall of 20 the housing 3. That is it is positioned substantially midway along the housing 3 in a depthwise direction of the housing. The purpose of this is to space the tag away from the outer wall of the housing to reduce the force of a shock wave from a blast as much as possible before it reaches the tag 5. The RFID tag has a unique identification number and transmits this identification 25 number in a way that can be picked up by a receiver when it is energized by radio energy. RFID tags are ubiquitous contrivance which is manufactured in large numbers for use in many applications and is available for off the shelf purchase. As the structure and function of RFID tags would be well known to persons skilled in the art they will not be described in further detail in this specification. 30 In the manufacture of the marker 1 the two housing parts 11 and 13 are each formed in separate moulding operations, e.g. injection moulding operations. The die which is used to mould the parts is not unduly complex. The housing parts are moulded from a hard and robust plastics material, e.g. BAKELITE TM or glass filled nylon. Each marker is assembled by placing an RFID tag within a locator on one housing 35 part. The tolerance and position of the locators ensures that the tag is positioned easily and 25 accurately in the correct position within the housing part. The marker is then assembled by snapping the other housing part onto the one housing part containing the RFID tag and the assembly of the marker is complete. In the illustrated embodiment, no adhesive or the like is required to complete the assembly process. However in other embodiments, solvent welding, 5 ultrasonic welding or adhesives can be used to more completely bond the two housing parts to each other. Figs. 4 to 8 show generally an apparatus for monitoring the movement of different ore blocks within an overall ore body. In these drawings the apparatus is indicated generally by the reference numeral 41. 10 The apparatus 41 comprises a plurality of markers 1 as described above dispersed within the ore body and also a reader shown generally by 43. In broad terms the function of the reader 43 is to read the identity of the RFID tag 5 of each marker 1 that comes into its range. The reader also reads the location and/or time stamp when it reads an RFID tag 5. The functionality of the RFID tag 5 within the marker 1 is shown schematically in 15 Figure 4. . The RFID tag 5 has a unique identification number 45 which is a combination of 1's and O's or binary code as shown in the drawing. The RFID tag 5 is energised by radio energy from the tag reader 43 and specifically an antenna 47 of the tag reader 43 when it comes into the range of the antenna, typically within 5 m of the antenna. In response to being energised 20 in this way the tag 5 sends out a return radio signal transmitting its unique identification number 45. The antenna 47 of the reader 43 sends out RF energy and when a marker 1 comes within range of the antenna the RF energy issuing from the antenna 47 energises the RFID tag 5 and causes it to send back its unique identification 45 by means of a return radio wave. 25 Fig. 5 is a schematic drawing showing the different components making up the apparatus 41 and how they interact with each other. In addition to the components described above with reference to Fig. 4, the apparatus 41 also includes a data collector and data processor which is typically in the form of a computer 49 having a database, that records the identity and time of each of the RFID tags 5 30 recorded by each of the readers 43. This then serves as the basis for tracking the progress of different ore blocks within an ore body and for indicating when the various ore blocks are undergoing the different unit operations such as crushing and milling. A plurality of markers 1 is placed in a particulate ore body at different positions in the ore body. These positions broadly demarcate ore body portions or blocks within the ore body. 35 Thus when the markers 1 are read by the readers in the plant it broadly indicates where the 26 associated ore block is within the plant and when it will be processed by the different unit operations. The apparatus includes a conveyor belt that is indicated broadly by reference numeral 51 and a stream of particulate material 53 to be processed is conveyed along an ore travel 5 path by the conveyor belt. Two types of readers are shown namely a stationary reader 43 that is placed in a fixed position along the path of the plant and also a portable device that is a hand held reader 57 that is carried around by an operator. The hand held readers 57 are used to log the initial positions of each of the markers 1 10 when they are first placed in positions within the ore material. In one form the markers 1 are placed in the rock material before it has been blasted. In another form the markers 1 are placed in the particulate material on the surface of the muck pile to mark different ore blocks or ore portions within the ore body. The apparatus also includes at least one stationary reader 43 that is positioned above 15 a conveyor belt 51. The reader 43 comprises a flattened body having two major surfaces 54 and 55 of broadly rectangular configuration. The reader 43 is orientated with its major surfaces 54, 55 extending horizontally at a position spaced about 1-1.5m above the conveyor belt 51. The long axis of the reader 43 extends in the direction of width of the conveyor belt 51 and extends across at least half of the 20 width of the conveyor belt 51. The orientation of the reader 43 is arranged in this horizontally extending orientation to increase the flux of radio energy directed down onto the conveyor belt 51. Further it increases the chance of locating markers 1 on the conveyor belt 51 irrespective of their position across the width of the conveyor belt 51. 25 The reader 43 is operatively coupled to a power supply for energising the antenna. This may be a mains power supply. The power supply may also be a solar panel for a remote installation as shown in the drawings. Fig. 7 is a schematic three dimensional view of a hand held reader 57 that is light enough to easily be carried around much like a mobile telephone. 30 The reader broadly includes a microprocessor module interfaced with an RFID reader, a GPS device for logging the initial positions of markers operatively coupled to the module, a data communication interface and an information database. Further the reader 57 includes a housing, an antenna, a clock for enabling a user to log a time stamp when each marker is placed, and a power supply such as a battery power 35 supply contained within the housing.

27 The hand held reader 57 has a data communication interface that is in the form of a screen 59 that displays information such as the identification of the marker 1 and its location as determined by the GPS position locator. The data collector and data processor in the form of the computer 49 that is shown in 5 Figure 5 includes a database (as described above) for collecting and organising data on the various tags 5 and the time when they are read by the readers 43 and 57. The computer 49 may be in the form of a PC, with an interface comprising a screen and a keyboard. Fig. 8 illustrates an example display on the screen of the computer forming the data collector and data processor. 10 Further the apparatus 41 may include a data communication device for facilitating communication between the various readers, both hand held readers and stationary fixed position readers. The data communication device may include cables hardwiring the components to each other. It may also include a wireless communication link. In use the hand held readers are used to log the location of each of the markers in the 15 initial rock body, whether it is still intact or whether it is blasted. This information is used together with information on the ore body being blasted to determine where the different ore blocks are located within the body prior to sending the particulate material into the processing plant. As shown in Figs. 5 and 6 once the particulate material has commenced travel along 20 the ore travel path, the markers 1 are conveyed along the belt 51 within the material 53. Radio energy that is transmitted by the reader 43 causes the markers 1 located in the particulate ore 53 on the conveyor belt 51 to be energized. This in turn causes the tag 5 within the marker 1 to send a signal back identifying the unique RFID tag 5 of that particular marker 1 which is received by the reader 43. The reader 43 then sends this information 25 through to the data collector which is the computer 49 which systematically logs this information in its database. Figs. 9 and 10 illustrate one example application of the apparatus in a mining environment. In this application one use of the apparatus can be to measure the movement of ore block boundaries or ore block interfaces particularly in complex ore bodies as a result of 30 the blasting of the host rock to break it up. In this application a plurality of markers 1 are placed in blast stemming holes 61 that are filled with explosive prior to a blast. The markers 1 are positioned spaced apart from each other across the area of the ore body to be blasted (when viewed in plan view) so that the results can give a good idea of rock movement.

28 Fig. 9 illustrates an operator placing a marker 1 in an explosive hole 61. Generally the marker 1 will be placed in a hole 61 such that it is received well within the hole 61, e.g. reasonable deep within the hole so that it is not shot out of the hole by the force of the blast. (It would not work to simply place the markers 1 on the surface of the rock body prior to the 5 blast). The markers do not need to be placed in each explosives hole. Generally the markers will be arranged spaced apart from each other broadly in the form of an array when the area being blasted is viewed in plan view. Further while it is not necessary for the markers to be placed in the same holes at the explosives Applicant has found that this is advantageous 10 because the holes are labour intensive and therefore expensive to drill. Further Applicant has established that its markers have a good survival rate, e.g. about 80%, when placed in the same holes as the explosives. After the explosives and markers have been packed into the blast holes or stemming holes the holes are closed up with tamping material. The location of the marker is then 15 logged by means of a hand held reader 57 as shown in Fig. 7. The explosives are then detonated to break up the rock body into pieces. This movement of the tags as a result of the blast can be used to calculate the lateral movement or dislocation of the surrounding region of the ore block as a result of the blast. This enables the three dimensional geological map of the different ore blocks in the 20 ore body to be adjusted to take into account the movement occurring as a result of blasting. That is the movement can be used to directly determine where the boundaries of the different ore blocks are located after the blast. This information in turn can be used in the subsequent processing of the ore to reduce ore dilution. That is the amount of ore being sent to the tailings dump is reduced as is the amount of waste being sent to the concentrator. The 25 movement of the ore block boundary as a result of the blasting has been identified as a major cause dilution and consequent loss of values in mining operations and associated mineral processing operations. Fig. 10 is a surface map of one example application of the invention and shows the initial location of the various markers 1 prior to the blast as well as the positions of the 30 markers 1 after the blast. This example shows clearly the movement of the rock body and hence the movement of the boundaries of the different ore blocks or ore body portions within the overall ore body. This movement is considerable and should therefore be taken into account by mine operators. The movement of ore block boundaries as a result of blasting has been ignored in many prior art mining practices of which the Applicant is aware.

29 Applicant has found that using this method can significantly reduce the ore dilution in a plant caused by discrepancies between the assumed ore body boundaries in a complex ore body and the actual ore block boundaries in such an ore once it has been blasted and broken up. 5 Figs. 11 and 12 illustrate an apparatus for tracking the progress of different ore blocks of an ore body through a mineral processing plant from the blast through to the SAG mill. This apparatus constitutes a different embodiment of the invention to that described above with reference to Figs. 9 and 10. In Figs. 11 and 12 the apparatus is indicated generally by numeral 71 and a mineral 10 processing plant is shown generally by numeral 73 for processing particulate material. The plant 73 comprises broadly a muckpile of broken rock 75 formed at the blast site and a crusher 77 for crushing the broken rock. It also includes a first conveyor 79 for conveying the broken rock to an intermediate heap 81 and then a second conveyor 83 for conveying the particulate material from the intermediate heap 81 to the mill 85, e.g. a SAG 15 mill. The plant 73 also includes a set of loaders, e.g. front end loaders 76 for transferring the broken rock from the muckpile 75 to the crusher 77. The loader 76 tips each load of particulate ore material into an open top of the crusher 77. The intermediate heap 81 also includes means for metering the flow of particulate 20 material from the heap 81 onto the second conveyor belt 83. The apparatus 71 comprises broadly markers 1 located within the particulate material shown by numeral 1 at various stages of progress through the plant 73. The markers 1 are the same as those described above and illustrated in Figs. 1 to 3. The marker 1 is sized to have a long dimension that is less than the distance between the operative crusher surfaces. 25 This helps to achieve a good survival rate of markers 1 passing through the crusher while they are still in a functional and operative state. The apparatus 1 also includes a hand held reader 87 that is used by an operator walking on top of the muck pile 75. The handheld reader 87 logs the ground position of each of the markers 1 after the blast has occupied and before the material is loaded into the 30 crusher 77. The apparatus 71 also includes a first stationary reader 89 that is positioned above the first conveyor belt 79 adjacent to the crusher 77. The apparatus 71 also includes a second stationary reader 91 that is mounted above the second conveyor 83 downstream of the intermediate heap 81.

30 Yet further the apparatus 71 also includes a data collector and data processor for collecting and organising and presenting information on the markers 1 based on the readings taken by the readers 5. The data collector and data processor typically comprises a computer 95 with a screen capture like that described above with reference to Fig. 8. Further in the 5 embodiment shown in the drawings the stationary readers 89 and 91 and the hand held reader 87 communicate wirelessly with the computer 95. Fig. 12 is a schematic longitudinal sectional view through a conveyor belt 79, 83 and the particulate material being carried on the belt 79, 83. This drawing shows schematically how the markers 1 can be used to mark out or delineate different ore blocks, shown 10 respectively by numerals 101, 103 and 105, traveling along the belt. In use the markers 1 are positioned in the rock body (either intact or broken) so as to indicate broadly the boundaries of different ore blocks 101, 103 and 105 within a complex ore body when used in combination with a three dimensional geological map of the ore body showing the ore boundaries in the rock body. The positions of these markers 1 both pre-blast 15 and post-blast are then logged on the data collection means using the hand held reader 87. Thereafter the particulate material is progressively loaded in small batches into the crusher 77 by means of the loaders 76. The first and second stationary readers 87, 89 log the time when the various markers 1 pass beneath them on the conveyor belts 79, 83. This then provides a guide to when the different ore blocks are being processed within the crusher 77 20 and in particular the mill 85. This information in turn can be used to improve simulation of the plant. The simulation in turn can be used to optimise operation of the plant. The markers are generally broken up when they are passed through the SAG mill. The markers and their component parts are not recovered and as a whole are consumed or destroyed within the mill in use. Further by virtue of their destruction in the SAG mill the 25 markers cannot track the movement of the ore blocks through the plant downstream of the mill. Thus in this embodiment the apparatus 71 is used to track the movement of ore blocks 101, 103, and 105 from a muck pile 75 at a blast site through the crusher 77 along a conveyor belt system 79, 83 and then into a comminution apparatus such as a SAG mill 85. 30 Fig. 13 is a schematic block-type diagram showing the in conceptual form a system in accordance with the invention for tracking the progress of an ore block forming part of a stream of particulate material along an ore travel path 154 through a mining process. In Fig. 13, reference numeral 150 refer generally to a system for tracking the progress of an ore block forming part of a stream of particulate material along an ore travel path 154.

31 The system 150 includes at least one marker 152 that is placed within a stream of particulate material to delineate an ore block that is to be tracked along the ore traveling path 154. The marker 152 includes an onboard storage arrangement 156 for storing unique 5 identification information for the marker 152. At least one detecting or reading arrangement, generally indicated by reference numeral 158, is placed along the ore traveling path 154 at a detection zone or a reading zone or reading point defining a detection position or reading position. Each detecting arrangement 158 is for detecting the marker 152 when it travels with the body of ore through the detection 10 zone. The marker 152 includes a marker body including a robust outer wall and defining an interior space within which a transponder 162 is mounted, as is explained in more detail above. The robust outer wall shields the onboard storage arrangement 156 and the 15 transponder 162 from damage that may be inflicted by the body of ore blocks or particulate ore material that entrain the marker. The transponder 162 is in the form of a radio frequency identification (RFID) tag and has unique identification information stored thereon. In this example, the detecting arrangement 158 includes an interrogating arrangement 164 in the form of an RFID reader device for continuously interrogating the detection zone for 20 detecting marker 150 when it travels with the body of ore blocks through the detection zone. A user may place more than one marker 152 within a body of ore blocks or particulate ore material, herein after referred to as an ore parcel, to increase the chance of detecting a marker 152, in use. Moreover, the user may place different markers within different types of ore parcels to not just track the progression of the ore parcel through the ore traveling path, 25 but also to identify the type of ore parcel that travels past a point along the ore traveling path 154. The system 150 further includes a computer apparatus 168 having a computer database 170 and a computer network interfacing arrangement 172. Similarly, each detecting arrangement 158 includes a terminal network interfacing arrangement 174 for establishing 30 communication over a wireless data communication network 176 with the computer network interfacing arrangement 172. Thus, information or data can be passed between the detecting arrangements 158 and the computer 168. The tracking of the ore is broadly done by logging initial relevant parameters of the marker 152 within the ore parcel and then logging relevant detected parameters of the marker 35 as it passes with the ore parcel thought the detection zones of the detecting arrangement 158.

32 The initial parameters and the detected parameters can then be used to obtain and indication of the progress of the ore parcel along the ore traveling path. Therefore, the system includes an initial logging arrangement, generally indicated by reference numerals 178 and 180 for logging initial information when the marker is placed 5 within the body of ore blocks and for logging information about an initial position of the body of ore blocks. The initial logging arrangement includes the transportable detecting or reading apparatus 178 that is in the form of a handheld RFID reader than also has a geographic locating apparatus in the form of a GPS. Once a marker is place within the ore parcel that is to be tracked, then the use reads 10 the identification information of the marker 152 and also determines the geographic position of the marker with the GPS. The handheld reader includes a database for storing the identification information of the marker 152, a data stamp, in other words a date and time when the marker 152 is placed within the ore parcel, and information from the GPS of the physical or geographical information of the position of the marker 152. 15 The hand-held reader includes a data communication interface and can thus be connected in data communication with the computer 168, for example by USB interface, and the initial information of the marker 152 stored on the transportable database can be downloaded with the computer 168 and stored on the computer database 170. An application 180 running on the computer forms thus part of the initial logging arrangement 178 and 180. 20 The RFID reader 164 interrogates the reader zone continuously and as soon as any one of the markers 152 enters the detecting zone, they announce their unique identification information to the reader. The reader passes this information to its network interfacing arrangement 158 which is in the form of a wireless modem that is in data communication with the computer 168. The detecting arrangement also includes a time stamp generating 25 arrangement for stamping the identification information with a time and date. The marker identification information and the time stamp is then transmitted to the computer 168 that can store the detected information on the computer database 170. The detection logging arrangement performs the function of capturing the detected information and is partly formed by a temporary data store 182 and an application 184 on the 30 computer 184. The system further includes a presenting arrangement 186 for interpreting and extracting the initial information and the detected information from the computer database 170 and for presenting is information in a format to a user by way of a graphical user interface. Having logged on the database the initial time and position of a marker and the later detected 35 time and position of the marker 152 clearly enables a user to retrieve valuable information 33 from the data, such as the time it took for an ore parcel to reach a certain detection point. Since the geographical positions of the detecting arrangement is known, a user knows when a specific type of ore parcel is within that detecting position along the ore travel path. This may be valuable information for optimizing the mineral processing process. 5 The detecting arrangements can be positioned along the ore traveling path at strategic locations, for example next to a conveyor belt, or in front of an ore crusher, or a SAG mill, and the like. An advantage of the marker described above is that it is robust and has a good chance of surviving in a functional form its travel through the plant from the muck pile to the 10 SAG mill. This is important for it to be able to be read by the readers at various positions in its progress through the plant. In particular the marker is sized so that it can pass between the jaws of a typical crusher so that most markers survive passage through the crusher. This is important for the invention to provide a cost effective way of tracking passage of an ore through a plant. 15 A further advantage is that the shape of the marker described and illustrated above is that it has tendency to orientate itself with one of its major surfaces in a broadly horizontally extending orientation when it is mixed up with a particulate ore material. It will generally settle with a major surface facing upwardly. This feature together with the RFID being arranged in a similar orientation within the housing has the effect that the RFID tag has its greatest surface 20 facing upwardly to receive radio energy from a reader positioned above the conveyor belt. This increases the likelihood that the tag will be read by the reader when it passes beneath it on the conveyor belt. A yet further advantage of the marker described above is that its construction enables it to have a good chance of surviving a blast if it is placed in a blast stemming hole prior to 25 blasting. The feature of having the RFID tag largely surrounded by an air space within the housing helps to dampen the shockwaves caused by blasting. This assists the RFID to survive the blast. The robust outer wall of the marker body also helps to achieve this objective. A further advantage of the marker described above is that RFID tags are widely used 30 in a number of diverse applications and are extremely reliable in operation. Their operation and manufacture has been fine tuned and they are available off the shelf at reasonable cost and even at low cost. The tags are manufactured by a number of manufacturers around the world in extremely large quantities. These factors contribute to this invention being such a cost effective solution to the problems addressed in this application. This is important as the 34 markers are ultimately consumed in use when they are passed through the SAG mill and are not reusable. A yet further advantage of this invention is that the markers are reasonably simple in construction and can be made fairly inexpensively. As described immediately above the RFID 5 tags are easily obtained and the housing can be formed by moulding the two housing parts in a simple moulding operation such as an injection moulding operation. Further the locating and mounting formations can be moulded integrally with the associated housing part and thus do not need to be assembled onto the housing part after it has been moulded. The markers are assembled in a simple assembly process by placing an RFID tag 10 within a locating formation of one housing part and then snapping another housing part into position on top of the tag and said one housing part. A yet further advantage is that the marker has no moving parts. A yet further advantage of the apparatus described above is that the RFID readers also use widely used and well established technology and can be obtained from commercial 15 sources of supply. This in turn helps the apparatus of this invention to operate in a reliable fashion. A yet further advantage of the apparatus described above is that the data collection means comprises a PC computer and database of the type which is freely available. Yet further the readers can communicate with the data collection means by well known and well 20 established hardwire means of communication and also by well known and well established wireless means of communication. A yet further advantage of the apparatus described above is that it has a hand held reader that can log an identity of an RFID tag and a position of the RFID tag by means of GPS. It also has a fixed position reader that logs RFID identity and the time stamp when the 25 tags pass the reader during their travel along an ore travel path. These two features give the apparatus a unique ability to deal with material in piles or heaps and also material traveling along conveyor belts. A further advantage of the method an apparatus described above is that it is able to track different blocks of ore through a plant even though the plant may have an intermediate 30 heap onto which the particulate material is discharged after the crusher and before it is transported to the mill. That is it is able to track an ore block along an ore travel path even though the travel of an ore block may be interrupted by it being placed on an intermediate heap for a variable length of time. Yet further the apparatus is able to track ore block through a plant even when different ores are blended together that have been mined at different times 35 and which have been drawn from different stockpiles.

35 The placing of a plurality of transponders over the ore block, e.g. substantially across the entire horizontal surface presented by the ore block, and then capturing information of the initial position of the transponders enables a map or grid of points that represent the ore block to be created. The method provides a two dimensional map of the 5 location of the transponders on the ore body, intact or broken, that indicates their position in a plane parallel to the surface of the ground. Some of the transponders can be positioned so that their initial positions can be used to indicate an ore block boundary. This is useful when the transponders are placed on or in an in situ block of ore so that movement of the ore block boundary movement as 10 a result of blasting can be indicated by the movement of the markers. This helps operators to make allowance for the movement of ore block boundaries in complex ores due to blasting. It is useful to read the transponders as they travel along an ore travel path as the ore is conveyed through a mineral processing plant to fine tune control of mineral 15 processes including unit operations such as milling that are influenced by ore type to enable an efficient processing of the ore. It will of course be realised that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto, as would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of 20 the invention as is herein set forth.

Claims

1. A method for tracking the travel of an ore block within a stream of particulate ore material travelling along an ore travel path during handling or processing of the particulate 5 ore material, the method including: placing a plurality of transponders in or on the ore block that is either intact or broken, while it is stationary and prior to the handling and processing thereof, the transponders being spaced apart from each other in or on the ore block; associating the transponders with the ore block in or on which they are placed; and 10 detecting the passage of the transponders past one or more reader zones along the ore travel path, thereby to track travel of the ore block within the stream of particulate ore material along the ore travel path.

2. A method for tracking the travel of an ore block according to claim 1, wherein the placing of the plurality of transponders includes placing at least some of the transponders 15 in associated holes in the ore block, and wherein the holes are arranged in a selected spatial relationship relative to each other.

3. A method for tracking the travel of an ore block according to claim 2, wherein the method includes allocating to each transponder a unique identification code (ID), and allocating a unique hole label to each hole in the ore block, and associating the unique 20 identification code of the transponder with the unique hole label of the hole within which it is placed.

4. A method for tracking the travel of an ore block according to claim 1 or claim 2, wherein the method includes allocating to each transponder an identification code and associating the identification code of each transponder with the ore block in which or on 25 which it is placed, and wherein the method further includes allocating a unique ore block label to each ore block, and associating the identification codes of the transponders that are placed on the ore block with the ore block label of the ore block on which or in which it is placed.

5. A method for tracking the travel of an ore block according to claim 4, wherein the 30 method further includes identifying the initial position of placement of each transponder on the ore block and associating the initial position with the unique identification code of the transponder, and wherein identifying the initial position of placement of said each transponder includes using a Global Positioning Device (GPS) to indicate the initial ground position of said each transponder. 37

6. A method for tracking the travel of an ore block according to claim 5, wherein the method includes entering or recording on a portable device one or more of the following pieces of information: the ore block label, one or more of the hole labels, the transponder IDs associated with the hole labels of the hole within which those particular transponders 5 are placed, the initial location information associated with each of the transponders placed in or on the ore block, and an initial time-stamp of information that records when the transponders are placed on the ore block.

7. A method for tracking the travel of an ore block according to claim 6, wherein the method includes storing the entered or recorded information on the portable device in 10 electronic format, and the method also includes downloading the stored information on the portable device from the portable device onto a computer system.

8. A method for tracking the travel of an ore block according to any one of claims 4 to 7, wherein detecting when the ore block travels past a reader zone along the ore travel path includes using a transponder reader to read the unique identification codes of the 15 transponders that travel past said reader zone, and from these identification codes determining the ore block that is travelling past the reader zone from these identification codes.

9. A method for tracking the travel of an ore block according to claim 8, wherein the method includes locating a plurality of transponder readers at spaced intervals along the 20 length of the ore travel path, and reading the unique identification codes of the transponders when they travel past each reader zone and then sending the unique identification codes of the transponders to the computer system for correlation with the ore block with which they were originally associated, whereby to track the passage of an ore block along the ore travel path. 25

10. A method for tracking the travel of an ore block according to claim 9, wherein the method includes allocating to each transponder reader a unique reader label, and storing the unique reader labels of the transponder readers on a database that is interfaced with the computer system, and wherein the method also includes keeping a record of the transponder identification codes that are detected by the readers, and of the reader labels 30 of the transponder readers that detected the transponder identification codes, and also generating a reader time-stamp each time a transponder is detected by a said reader.

11. A method for tracking the travel of an ore block according to claim 10, wherein the method includes presenting the information on the database selectively to the computer system, to enable a user to identify the last detected position of the ore block along the 35 ore travel path and the time when the ore block was detected. 38

12. A method for tracking the travel of an ore block according to any one of claims 1 to 11, wherein each transponder is an RFID device, and wherein each transponder reader is an RFID reader.

13. A marker for placement in or on an ore block that is either intact or broken, for 5 tracking the travel of the ore block along an ore travel path within a stream of particulate ore material, the marker including: a transponder; and a marker body defining an interior space within which the transponder is received, the marker body having a robust outer wall for shielding the transponder from damage 10 due to impact and collision with particulate ore material within the stream within which it is entrained.

14. A marker for placement in or on an ore block according to claim 13, wherein the transponder is positioned within the interior space such that it is spaced inwardly away from the outer wall and a space or a spacing is defined between the transponder and the 15 outer wall, and wherein the spacing defined between the transponder and the outer wall is at least partially occupied by a shock absorbing material.

15. A marker for placement in or on an ore block according to claim 14, including at least one mounting formation in the interior space of the marker body, the mounting formation being for mounting the transponder within the interior space of the marker body 20 spaced inwardly from the outer wall.

16. A marker for placement in or on an ore block according to claim 15, wherein the mounting formation includes an inner wall inside the interior of the marker body, that is spaced from the outer wall defining the spacing between the inner wall and outer wall, and wherein the transponder is received within the inner wall. 25

17. A marker for placement in or on an ore block according to any one of claims 13 to 16, wherein the outer wall is made of a resilient material, and wherein the outer wall has a thickness of 0.3 cm to 0.8 cm, and wherein the marker body has a diameter of 3 to 10 cm, and a depth or height of 2 to 4 cm, and wherein the transponder is a radio frequency identification (RFID) tag. 30

18. A marker for placement in or on an ore block according to claim 17, wherein the outer wall includes opposed major end walls and a minor sidewall extending between the opposed major end walls, and the opposed major end walls are sized and shaped to encourage the marker to come to rest with one of its major walls resting on a support surface and the other major surface facing upwardly. 39

19. A marker for placement in or on an ore block according to claim 18, wherein the outer wall is shaped and sized to form a close-ended shallow circular cylindrical body having said major end walls in the form of two opposed generally circular end walls, and the minor side wall is in the form of a shallow cylindrical sidewall extending between the 5 end walls and wherein the sidewall merges with the end walls to form rounded circumferential edges at their transition.

20. A marker for placement in or on an ore block according to claim 19, wherein the RFID tag includes a flattened RFID body having two opposed major surfaces and the direction of greatest flux of the RFID tag is arranged to be orthogonal to the major surfaces 10 of the RFID body, and wherein the RFID body is mounted within the marker body with an orientation so that its direction of greatest flux is vertically extending when the marker body orientates itself resting on one of its major surfaces whereby to render the RFID tag susceptible of being read by an RFID reader positioned above the ore body travelling along the ore travel path. 15

21. A marker for placement in or on an ore block according to any one of claims 13 to 20, wherein the marker body includes two body parts that are attachable to each other to form the marker body by means of complementary clip formations, and wherein each body part includes a mounting formation and the RFID tag can be clamped tightly between the two mounting formations when the body parts are attached to each other. 20

22. A method for tracking the travel of an ore block within a stream of particulate ore material travelling along an ore travel path during handling or processing of the particulate ore material, substantially as herein described in the detailed description with reference to the drawings.

23. A marker for placement in or on an ore block that is either intact or broken 25 substantially in accordance with any one of the embodiments described in the detailed description with reference to the drawings.