WO2013056313A1

WO2013056313A1 - Autonomous method and system for determining elemental composition of an ore

Info

Publication number: WO2013056313A1
Application number: PCT/AU2012/001274
Authority: WO
Inventors: Geoffrey Alan CARTER; Gale Leigh PAULSEN; Paolo Moreschini
Original assignee: Technological Resources Pty Ltd
Priority date: 2011-10-20
Filing date: 2012-10-18
Publication date: 2013-04-25
Also published as: PE20141367A1; CA2852744A1; AU2012325680A1; CL2014000997A1; CN103975126A; IN2014CN03041A; BR112014009592A2

Abstract

A method (10) for autonomously determining an elemental composition of an ore involves an initial step (12) of conveying a stream of the ore past a moisture measurement system and an analyser. At step (14) the moisture measurement system operates to obtain moisture content data of the ore. As the stream of ore subsequently passes the analyser, the analyser at step (16) operates to obtain raw elemental composition data of the ore. The moisture content data and the raw elemental composition data are provided as inputs to compensation step (18). In the compensation step (18) one or more data compensation or correction methods or techniques are performed to provide moisture corrected elemental composition data of the ore. This compensated data is provided at step (20).

Description

AUTONOMOUS METHOD AND SYSTEM FOR DETERMINING ELEMENTAL

COMPOSITION OF AN ORE

Technical Field

An apparatus and method are disclosed for autonomously determining elemental composition of an ore. The method and system have regard to moisture content of the ore and provide moisture corrected elemental composition data of the ore.

Background Art

Determining the elemental composition of ore is critical for maximising the profit of an ore body. In drill and blast mining, drill cuttings formed by drilling blast holes in an ore bench are collected and taken to a laboratory for assaying in order to determine the elemental composition of the ore in the bench. To maintain consistency and assaying accuracy, the cuttings are preconditioned to ensure they have a prescribed moisture content. For example, if moisture content is above a predetermined range, the cuttings may be subjected to heating to reduce moisture content. The elemental composition of the cuttings determined from the assaying is communicated to mine planners who are able to plan a blasting sequence and subsequent processing of the ore to maximise profit. The above reference to the background art does not constitute an admission that the art forms a part of the common general knowledge of a person of ordinary skill in the art. The above reference is also not intended to limit the application of the method and system as disclosed herein. Summary of the Disclosure

In a first aspect there is disclosed a method of determining an elemental composition of an ore, said method comprising the autonomous steps of:

conveying a stream of ore past a moisture measurement system and an analyser;

operating the moisture measurement system to obtain moisture content data of the ore; operating the analyser to obtain raw elemental composition data of the ore; and,

compensating the raw elemental composition data by performing a data correction process using the moisture content data to output moisture-corrected elemental composition data of the ore.

In one embodiment obtaining the moisture content data and obtaining the elemental composition data are performed continuously on a moving stream of ore.

In one embodiment the operating and compensating are autonomously performed in real time.

In one embodiment operating the analyser comprises operating a laser induced breakdown spectrometer.

In one embodiment the method comprises obtaining the moisture content data as one or more of: average moisture content per unit volume of ore; median moisture content per unit volume of ore; highest moisture content per unit volume of ore; and lowest moisture content per unit volume of ore.

In one embodiment the moisture measurement system is a near infrared moisture measuring system. In one embodiment measurement system is done using a microwave based moisture measuring system.

In one embodiment the moisture measurement system is one of two or more moisture measuring systems each of which are based on different

measurement methodologies.

In one embodiment the two or more moisture measuring systems comprise at least a near infrared moisture measuring system and a microwave based moisture measuring system.

In one embodiment the step of compensating the data comprises using one, or a combination of two or more, of the following data correction methods: a look up table, principle component regression analysis, cluster and regression analysis, search match method, Gaussian process, whole pattern method, and condition based peak method. In one embodiment performing the data correction process comprises using a combination of a look up table and search and match method.

In one embodiment the data correction method comprises any one, or a combination of two or more of: a lookup table correction method; principal component regression analysis; cluster and regression analysis; search and match method; a Gaussian method; a whole pattern method; and a condition- based peak method.

In a second aspect there is disclosed an autonomous system for determining an elemental composition of an ore, said system comprising:

a moisture content measuring system capable of providing ore moisture content data;

an analyser capable of providing raw elemental composition data of the ore;

a conveyor capable of conveying a stream of ore past the moisture content measuring system and the analyser; and,

a data processor arranged to autonomously control operation of the measuring system, the analyser and the conveyor, and to subsequently compensate the raw elemental composition data by performing a data correction process using the moisture content data to produce moisture- corrected elemental composition data of the ore.

In one embodiment the analyser is a laser induced breakdown spectrometer. In one embodiment the moisture content measuring system is arranged to produce moisture content data comprising one or more of: average moisture content; median moisture content; highest moisture content; and lowest moisture content, per unit volume of ore conveyed past the moisture content measuring system per unit of time by the conveyor.

In one embodiment the moisture content measuring system is a near infrared moisture measuring system. In one embodiment the moisture content measuring system is a microwave based moisture measuring system.

In one embodiment the moisture content measuring system is one of two or more moisture content measuring systems each of which is based on different methodologies to obtain the moisture content data.

In one embodiment the two or more moisture content measuring system comprises a near infrared moisture measuring system and a microwave based moisture measuring system operating simultaneously to obtain the moisture content data.

In one embodiment the data processor is configured to perform one or a combination of two or more of the following data correction methods: a look up table, principle component regression analysis, cluster and regression analysis, search match method, Gaussian process, whole pattern method, and condition based peak method.

In one embodiment the data processor is configured to correct the raw data by a combination of a look up table correction method and search and match method.

In one embodiment the system comprises a drill rig arranged to drill holes in the ground and produce drill cuttings, wherein the moisture content measuring system, analyser and processor are supported on the rig and wherein the ore comprises a sample of the drill cuttings.

In one embodiment the system comprises a transmitter arranged to transmit the moisture-corrected elemental composition data to a remote location.

In a third aspect there is disclosed an autonomous drill rig for drilling blast-holes at a mine, said rig comprising: a drill operable to drill a blast hole and produce drill cuttings; and, the autonomous system for determining an elemental composition of an ore according to the second aspect; wherein the drill cutting are used as a source for the ore for the steam of ore. Brief Description of the Drawings

Notwithstanding any other forms which may fall within the scope of the apparatus and method as set forth in the Summary, specific embodiments will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 shows a flow diagram of one embodiment of the method; Figure 2 is a block diagram of one embodiment of the system. Detailed Description of Specific Embodiments

Embodiments of the system and method are described in the context of drill and blast mining. In drill and blast mining an array of blast holes is drilled into a bench of ore. Holes are drilled by one or more mobile drill rigs on the bench. As a hole is being drilled drill cuttings from the hole are deposited on the surface of the bench and form a cone-like structure about an associated drill string. The holes are subsequently charged with an explosive and the explosive detonated to fracture the bench into manageable sized rocks and boulders for processing. When embodiments of the system and method are used in the context of drill blast mining, the drill cuttings produced by operation of the drill rig provide a source of ore in relation to which the method and system are practised.

Figure 1 depicts an embodiment of a method 10 for autonomously determining an elemental composition of an ore. The term "ore" is intended to denote a solid naturally occurring rock that contains, or is an aggregate of minerals from which metal or other useful or valuable constituents can be extracted. Thus determining the elemental composition of the ore includes determining the elemental composition of minerals in or of the ore. In this instance, the ore is provided as drill cuttings derived by the operation of a drill rig used in drill and blast mining as described above. At an initial step 12 in the method 10 a stream of ore is autonomously conveyed past a moisture measurement system and an analyser. At step 14 the moisture measurement system operates to obtain moisture content data of the ore. As the stream of ore subsequently passes the analyser, the analyser at step 16 operates to obtain raw elemental composition data of the ore. The moisture content data and the raw elemental composition data are provided as inputs to compensation step 18 in the method 10. In the compensation step 18 one or more data compensation or correction methods or techniques are performed to provide moisture corrected elemental composition data of the ore. This compensated data is provided at step 20 of the method 10.

Steps 14 and 16 are generally performed simultaneously. But depending on the target zones for the moisture measurement system and analyser they may derive data from different ore samples. This is taken into account in the compensation step 18 and explained further below.

In the event that the moisture measurement system and analyser take readings at the same target zone then the respective moisture content data and raw elemental composition data relate to the same volume or sample or ore. In this case no additional processing is required at or by step 18.

However if the moisture measurement system and analyser have different target zones (i.e. take readings at spaced locations in the travelling ore stream), then the compensation process at step 18 is modified to also correlate the moisture content data with the raw elemental composition data to relate to the same volume of ore. In one embodiment this may be achieved by providing as an input to the compensation step 18 the instantaneous speed of the conveyed stream of ore. Assuming the distance between the respective target zones for the moisture measurement system and the analyser is known, then with knowledge of the speed of the conveyed stream of ore, the moisture content data can be readily correlated with the raw elemental composition data.

The compensation process at step 18 is performed in real time to produce the corrected data output at step 20 at substantially the same time as the ore has passed through the analyser.

Step 12 may be performed by a conveyor which at one end receives a sample of drill cuttings produced by operation of the drill and conveys the cuttings past the moisture measurement system and the analyser. An example of such a conveyor is set out in Applicant's co-pending application No. 201 1900230. Such a conveyor is particularly well suited to use in the context of drill and blast mining. However embodiments of the system and method are not limited to such a conveyor system and alternate conveying systems or techniques may be used.

Step 14 may be performed to obtain one or more different types of moisture content data. For example the moisture content data obtained may be: average moisture content per volume of ore; median moisture content per volume of ore; highest moisture content per volume of ore; and, lowest moisture content per volume of ore. During the compensation process at step 18, one or more of such moisture content data may be used.

Further, step 14 is not dependent upon any particular methodology for measuring moisture content. For example step 14 may be performed using an infrared moisture measurement system such as the Process Sensors

Corporation NIR moisture sensor; a microwave-based moisture measurement system such as the Hydronix Hydro-probe or a combination of both. However, it should be understood that step 14 may utilise other moisture measurement systems.

Step 16 may be performed by any one of many different types of analysers. One example of an analyser that may be used in performing step 16 is a laser induced breakdown spectrometer ("LIBS"). However step 16 may be performed by other analysers including for example XRF, XRD, NIR or NQR analysers; spark induced breakdown spectrometers; or, atomic emission spectrometers.

The compensation step 18 may be performed using one, or a combination of two or more, data correction methods and techniques such as but not limited to: a lookup table correction method; principal component regression analysis; cluster and regression analysis; search and match method; Gaussian method; whole pattern method; and, condition-based peak method. For example in one embodiment step 18 may comprise using a combination of the lookup table correction method and the search and match method.

Figure 2 illustrates an embodiment of a system 30 for implementing the method 10. System 30 comprises a conveyor 32, a moisture measurement system 34, an analyser 36 and a processor 38. Conveyor 32 is arranged to convey a stream of ore 39 past the moisture measurement system 34 and analyser 36. In the system 30, the conveyor 32 operates to move the stream 39 from right to left so that the stream initially passes the moisture measurement system 34 and subsequently passes the analyser 36. Thereafter the ore can be dumped from the conveyor 32. The moisture measurement system 34 has a target zone 40 at which it takes moisture readings of the passing ore stream 39. Similarly, the analyser 36 has a target zone 42 at which it analyses the passing ore stream 39. In this embodiment the target zones 40 and 42 are separated by distance D. It is however to be recognised that in alternate embodiments the moisture measurement system 34 and analyser 36 may be arranged so as to have coincident or identical target zones. In that event, there is no separation distance between the target zones so that D=0.

Moisture content data from the moisture measurement system 34 is

communicated to the processor 38 together with raw elemental composition data produced by the analyser 36. In this embodiment where D > 0 a speed sensor 44 that measures instantaneous speed of the conveyor 32 also communicates the measured speed to the processor 38.

The processor 38 is programmed or otherwise arranged to produce moisture corrected elemental composition data by performing a data correction process utilising the moisture composition data and the raw elemental composition data. When D > 0 the processor 38 also utilises conveyor speed and the distance D to correlate moisture content data and the raw elemental composition data so as to relate to the same volume or portion of ore in the ore stream 39. The processor 38 is programmed or otherwise arranged to perform any one or more of the compensation methods and techniques described herein above.

In addition, the processor 38 may be further programmed to autonomously control the operation of the conveyor 32, moisture measurement system 34 and analyser 36. For example the processor 38 may control the speed of a conveyor 32 (for example by controlling a conveyor motor 48) to maintain a preferred volume of ore passing through the target zones 40 and 42. Processor 38 may also control a sampling or measuring rate of the moisture measurement system 34 and analyser 36.

System 30 can be mounted on a mobile drill rig and operable to enable the autonomous determination of elemental composition of an ore while drilling is being conducted by the drill rig. Thus method 10 and system 30 enable in situ autonomous determination of elemental composition which is compensated for moisture content. The moisture corrected elemental composition data obtained by method 10 and system 30 may be stored in a memory device associated with the processor 38 and/or communicated to a remote location via a communication system 46 associated with the processor 38. This enables mine planners at a remote location to analyse the elemental composition of the ore and in particular a bench of ore utilising real time data produced autonomously at the location of the ore itself.

It is to be appreciated that the current method and system described herein allow for the elemental analysis of ore directly on a drill rig without requiring the ore to be sent off to a laboratory for analysis. This allows much more rapid analysis of the ore with associated advances in bench composition analyses and mine planning.

Whilst specific method and system embodiments have been described, it should be appreciated that the method and system may be embodied in many other forms. Further, while the present embodiments are described in the context of drill and blast mining, they are not limited to such application and may be used in any instance where it is desirable to autonomously obtain moisture compensated elemental composition of an ore. For example the ore in relation to which the method 10 and system 30 operate need not be acquired from drill cuttings generated by drilling of a blast hole. They may for example be generated by an auger which is operated for the sole purpose of providing ore samples. Further, the conveyor 32 may take forms other than an endless belt conveyor of the type illustrated in Figure 2.

In the claims which follow, and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word "comprise" and variations such as "comprises" or "comprising" are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence of additional or further features in various embodiments of the system and method as disclosed herein.

Claims

Claims:

1 . A method of determining an elemental composition of an ore, said method comprising the autonomous steps of:

conveying a stream of ore past a moisture measurement system and an analyser;

operating the moisture measurement system to obtain moisture content data of the ore;

operating the analyser to obtain raw elemental composition data of the ore; and

compensating the raw elemental composition data by performing a data correction process using the moisture content data to produce moisture- corrected elemental composition data of the ore.

2. The method according to claim 1 wherein obtaining the moisture content data and obtaining the raw elemental composition data are performed continuously on a moving stream of ore.

3. The method according to claim 1 or 2 wherein the operating and compensating are autonomously performed in real time.

4. The method according to any one of claims 1 to 3 wherein operating the analyser comprises operating a laser induced breakdown spectrometer.

5. The method according to any one of claims 1 to 4 comprising obtaining the moisture content data as one or more of: an average moisture content per unit volume of ore; a median moisture content per unit volume of ore; a highest moisture content per unit volume of ore; and a lowest moisture content per unit volume of ore.

6. The method according to any one of claims 1 to 5 wherein the moisture measurement system is a near infrared moisture measuring system.

7. The method according to any one of claims 1 to 5 wherein the moisture measurement system is a microwave based moisture measuring system.

8. The method according to any one of claims 1 to 5 wherein the moisture measurement system is one of two or more moisture measurement systems each of which are based on different measurement methodologies.

9. The method according to claim 8 wherein the two or more moisture content measuring systems comprises at least: a near infrared moisture measuring system; and a microwave based moisture measuring system.

10. The method according to any one of claims 1 to 9 wherein the step of compensating the data comprises using one, or a combination of two or more, of the following data correction methods: a look up table, principle component regression analysis, cluster and regression analysis, search match method, Gaussian process, whole pattern method, and condition based peak method.

1 1. The method according to any one of claims 1 to 10 wherein performing the data correction process comprises using a combination of a look up table and search and match method.

12. The method according to any one of claims 1 to 1 1 wherein the data correction method comprises any one, or a combination of two or more of: a lookup table correction method; principal component regression analysis; cluster and regression analysis; search and match method; a Gaussian method; a whole pattern method; and a condition-based peak method.

13. An autonomous system for determining an elemental composition of an ore, said system comprising:

an analyser capable of providing raw elemental composition data of the ore;

a conveyor capable of conveying a stream of ore past the moisture content measuring system and the analyser; and

14. The system for determining elemental composition of an ore according to claim 13 wherein the analyser is a laser induced breakdown spectrometer.

15. The system for determining elemental composition of an ore according to claim 13 or 14 wherein the moisture content measuring system is arranged to produce moisture content data comprising one or more of: average moisture content; median moisture content; highest moisture content; and lowest moisture content, per unit volume of ore conveyed past the moisture content measuring system per unit of time by the conveyor.

16. The system for determining elemental composition of an ore according to any one of claims 13 to 15 wherein the moisture content measuring system is a near infrared moisture measuring system.

17. The system for determining elemental composition of an ore according to any one of claims 13 to 15 wherein the moisture content measuring system is a microwave based moisture measuring system.

18. The system for determining elemental composition of an ore according to any one of claims 13 to 15 wherein the moisture content measuring system is one of two or more moisture content measuring systems each of which is based on different measurement methodologies to obtain the moisture content data.

19. The system for determining elemental composition of an ore according to claim 18 wherein the moisture content measuring system comprises a near infrared moisture measuring system and a microwave based moisture measuring system operating simultaneously to obtain the moisture content data.

20. The system for determining elemental composition of an ore according to any one of claims 13 to 19 wherein the data processor is configured to perform any one, or a combination of two or more, of the following data correction methods: a look up table correction method, principle component regression analysis, cluster and regression analysis, a search match method, a Gaussian method, a whole pattern method, and condition based peak method.

21. The system for determining elemental composition of an ore according to claim 20 wherein the data processor is configured to correct the raw data by a combination of the look up table correction method and the search and match method.

22. The system for determining elemental composition of an ore according to any one of claims 13 to 21 comprising: a drill rig arranged to drill holes in the ground and produce drill cuttings, wherein the moisture content measuring system, analyser and data processor are supported on the rig and wherein the ore comprises a sample of the drill cuttings.

23. The system for determining elemental composition of an ore according to any one of claims 13 to 22 comprising: a transmitter arranged to transmit the moisture-corrected elemental composition data to a remote location.

24. An autonomous drill rig for drilling blast-holes at a mine, said rig comprising: a drill operable to drill a blast hole and produce drill cuttings; and, the autonomous system for determining an elemental composition of an ore according to any one of claims 13 to 21 , wherein the rig is arranged to use the drill cutting as a source of ore for the steam of ore.