WO2005116392A1

WO2005116392A1 - Core analysis

Info

Publication number: WO2005116392A1
Application number: PCT/IB2005/001445
Authority: WO
Inventors: John Lisle Orpen
Original assignee: John Lisle Orpen
Priority date: 2004-05-26
Filing date: 2005-05-26
Publication date: 2005-12-08
Also published as: ZA200610611B

Abstract

The present invention provides a portable core analysis machine (1; 40), particularly for logging data from drilled core samples of rock. Also provided is a method of logging this data from a rock core. The core analysis machine has a roller bed (6; 49) provided by a pair of elongate parallel rollers (7; 51) connected for synchronized rotation to rotatably support a core sample (4; 43) along their length. An indicator (14; 41) is pivotably secured to :a slide (13) to be movable along a guide (12) which lies parallel to the roller bed. A roller of the roller bed is connected to communicate rotation to a first rotary encoder (11) and the indicator is connected to communicate pivoting to a second rotary encoder (19). The indicator preferably pivots about an axis (48) radial to and centrally above the axis (50) of a core (43) located on the roller bed. A marker (15; 41) is also mounted on the slide which is connected to communicate movement along the guide to a third rotary encoder (24). The indicator and marker are provided, in a preferred embodiment, by a light source (41) directed towards the roller bed with the light (42) concentrated in a plane. The machine is connectable to a computer (25) enabled by suitable core analysis software and will include image and/or physical property recording equipment mounted for movement along the roller bed. The method of logging rock core data comprises removing a core sample from the core barrel of a drill rig, placing the core sample on a roller bed, marking the core with an orientation line and measuring and recording details of the core at the drilling site. The details of the core are downloaded to an electronic database.

Description

CORE ANALYSIS

FIELD OF THE INVENTION

The invention relates to a core analysis machine, particularly for logging data from drilled core samples of rock. The invention extends to a method of logging this data.

BACKGROUND TO THE INVENTION

The successful mining of ore-bodies, safe construction of massive structures such as high rise buildings and dam walls, and tunneling for civil works are all dependent on a thorough knowledge of the geology of the ground. A three- dimensional understanding of the subsurface rock structure is developed from geological mapping, along with geophysical and geochemical surveys. However, the predictive power of such three-dimensional models is substantially limited without data from reliable and accurate measurements of all the subsurface geological structures.

Diamond drilling is used to bore deep into the earth with the aim of producing continuous cylinders of rock, which are termed "core". These core samples intersect the geological structures and can be analyzed to determine rock mass behavior when excavating or loading with additional weight. In the normal course of events, the drilled core samples are delivered by the driller, in 1 meter core trays, to a core-shed where they are accumulated for examination and logging by a geologist. Ideally, the cores are extracted from the ground in 3 or 6 meter lengths but these are seldom continuous, being broken up by natural or mechanical fractures. Transportation and storage of the core prior to logging frequently results in serious data loss through bad handling, oxidation, weathering or dehydration. In addition, current core logging methods are often too slow for the collection of a complete suite of data ahead of ground development. This then has to proceed under-researched as it were, or else be hampered by the high cost of delays.

There are two major geological structures in a rock core that require measurement. The first are planar features which include bedding, fracture, joint, fault or foliation planes. The second are linear features such as mineral lineations and fault slickensides. The measurements required of these features should enable their orientation in the rock mass, before the core was drilled and extracted from the ground, to be described. In other words, the strike and dip of any planar feature and the plunge and plunge direction of any linear feature must be computed from measurements made on suitably prepared core. This requires that each core sample must be orientated or referenced with respect to the in situ geographic vertical plane and in situ core axis azimuth and inclination.

The intersection of the geographic vertical plane is thus scribed or drawn along the length of the core, either along the top or the bottom. Different methods are used to properly locate this marking. An arrow along this reference line indicating the end of hole direction will also be drawn. This marking requires quality core with minimal mechanical or driller induced fracturing or grinding.

The orientation of the core axis is obtained by relating depth, from which the piece of core was extracted, to the borehole survey azimuth and inclination data for that depth. The core is lithologically logged by visual inspection and, if oriented, the attitude of any geological structures can be measured relative to the core axis. From this data is derived the true dip of the plane in the ground by rotating it about the azimuth and inclination of the core axis, obtained from the borehole survey.

Apart from the time required for such measurements, using current logging methods, the situation is further exacerbated by the false assumption that geotechnical drilling is specialized and hence the significantly higher costs of doing it are justified. The only real difference is that such core has to be oriented.

OBJECT OF THE INVENTION

It is an object of the present invention to provide a core analysis machine as means which facilitates recording or logging details of a core sample and also a method of logging data from a core sample.

SUMMARY OF THE INVENTION

In accordance with this invention there is provided a core analysis machine comprising a roller bed to rotatably support a core sample and an indicator pivotably secured to a slide movable along a guide parallel to the roller bed, the roller bed having a roller connected to transmit rotation to a first electronic reader and the indicator connected to transmit pivoting to a second electronic reader.

The invention further provides for a marker to be mounted on a slide movable along a guide parallel to the roller bed with the slide connected to transmit movement along the guide to a third electronic reader.

Further features of the invention provide for the indicator to pivot about an axis radial to the axis of a core located on the roller bed; for the indicator to pivot about an axis located centrally above the roller bed; and for the indicator and marker to be supported by the same slide. Further features of the invention provide for the indicator and marker to be a light source directed towards the roller bed; and for the light to be concentrated in a plane. Alternatively, the indicator is a pair of parallel limbs, one on either side of the roller bed, connected at their free ends.

Further features of the invention provide for the electronic readers to respectively be selected from the group comprising rotary encoders, linear encoders and potentiometers; for the roller bed to be provided by a pair of elongate parallel rollers connected for synchronized rotation; and for the machine to be portable.

Further features of the invention provide for the machine to be connectable to a computer enabled by suitable core analysis software; for the machine to include image and/or physical property recording equipment mounted for movement along the roller bed; and for the computer be enabled by suitable controller software to operate the recording equipment.

In accordance with another aspect of this invention, there is provided a method of logging rock core data comprising: removing a core sample from the core barrel of a drill rig; placing the core sample on a roller bed; and measuring and recording details of the core at the drilling site.

The invention further provides for the method to include marking the core with an orientation line when it is on the roller bed.

Further features of the invention provide for the details of the core to be recorded on an electronic database; and for the roller bed to be that of a core analysis machine as defined above.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein: Figure 1 shows a side elevation of one embodiment of a core analysis machine;

Figure 2 shows a plan view of the machine in Figure 1 ; Figure 3 shows a schematic plan view of the machine's electronics;

Figure 4 shows the measurement of the azimuth (β) angle of a geological structural plane in a section of core; Figure 5 shows the measurement of the dip (α) angle for the structural plane in Figure 4; Figure 6 shows the measurement of the theta (θ) angle of a lineation contained within a structural plane; Figure 7 shows an alternative embodiment of a core analysis machine; Figure 8 shows the use of a light beam to measure depth using the machine in Figure 7; Figure 9 shows use of the light beam to measure the attitude of a structure relative to the core axis (β and α angles) in one operation; Figure 10 shows use of the light beam to measure the theta (θ) angle or plunge of a lineation seen in an open fracture; and Figure 11 shows schematic illustrations of angle measurements using the machine in Figure 7.

DETAILED DESCRIPTION OF THE INVENTION

Referring to Figures 1 to 3 of the drawings, a core analysis machine (1 ) is provided in a portable case (2). The front wall of the case extends downwardly from the lid (3). This affords desirable access to front of the machine (1) for analysis of a core sample (4) when the lid (3) is open, as shown.

The machine (1) has an elongate frame (5) which supports a roller bed (6). The roller bed (6) comprises a pair of parallel, spaced apart rollers (7). The rollers (7) are fixedly mounted on rotatable axles, which on one side extend through an end plate (8). The end plate (8) forms a wall for an electronics box (21). The ends of the axles which extend through the plate (8) are secured in gears (9). A third gear (10) connects those on the axles to synchronize rotation of the rollers (7). One of the roller (7) axles is connected to a first rotary encoder (11 ).

The frame (5) provides a guide (12) to which a slide (13) is movably secured. The guide (12) extends parallel to the roller bed (6). An indicator (14) is pivotably secured to the slide (13). Also secured to the slide (13) is a point marker (15). The marker is provided as a metal rod (15) with a sharpened end mounted perpendicular to the roller bed (6) on a fixed arm (16). The arm (16) extends upwardly from the slide (13) at the rear of the roller bed (6). The arm (16) is bent to support the rod (15) centrally over the roller bed (6). An adjusting screw (15.1 ) allows the rod (15) to be moved vertically towards or away from the bed (6). This accommodates core samples (4) of different diameter.

The indicator (14) is provided as a pair of connected limbs (17), one on either side of the roller bed (6). The limbs (17) extend upwardly from pivot pins (not shown) and are connected at their free ends. A fastening screw arrangement (18) is fixed to the front pivot pin. The rear pin is connected to a second rotary encoder (19).

A pair of pulleys (20) are mounted on the underside of the frame (5) spaced apart along its length. One pulley (20.1) is under the electronics box (21 ) to one end of the roller bed (6). The other pulley (20.2) is under the roller bed (6) towards its other end. A continuous belt (22) which runs on the pulleys (20) is secured at one point to the slide (13). This arrangement converts movement of the slide (13) along the guide (12) to rotation of the pulleys (20). The pulley (20.1) is connected to transmit this rotation to a third rotary encoder (24) in the electronics box (21 ).

In use, the machine (1) is connected to a computer, shown as a laptop (25) in Figure 1. The computer (25) is enabled by a suitable software program. A serial cable plug socket (21.1 ) is provided in the outer wall of the electronics box (21 ). A serial cable will usually be connected to the computer through a USB adaptor and cable. It will be appreciated that a suitable wireless connection could also be established with the appropriate equipment. The machine (1) includes a battery (not shown) which will conveniently be located in the box (21). An electrical plug socket (21.2) for connection to an external power source, such as a generator, is also provided. The machine (1 ) can be run off such a source while the battery is charged for portable use.

The box (21) also contains the necessary electronic interface equipment (21.3) which connects the encoders to the computer (25). Such equipment, which will depend to some extent on features of the machine which may vary, will be within the competence and understanding of a suitably skilled person. An on/off switch (not shown) will also be provided on the box (21).

Referring now also to Figures 4 and 5, which illustrate on a section of core, the measurement of the azimuth or beta (β) angle and dip or alpha (α) angle of the plane of a geological structure (26). If the borehole path survey is available and is preloaded into the computer database, the β and α angle can automatically be rotated to their in situ values.

A structural plane (26) inclined relative to a core sample forms an ellipse around the cylindrical surface of the core (4). It is also thus sometimes also referred to as the ellipse (26).

With an oriented core (4), the machine (1) provides a goniometer to measure the attitude of geological structures (26) relative to the core axis (27). The core (4) is placed on the roller bed (6) with its lower end to the right of the machine (1 ) shown in the drawings. The lower end is indicated by the end-of-hole arrow (29), marked on the reference or orientation line (28).

The third encoder (24) is calibrated for linear measurement of the displacement of the slide (13) along the guide (12). The reference line (28) on the core (4) is aligned in the vertical plane (30), directly under the point of the depth rod (15). The rod (15) is moved to the left hand end of the core (4) segment where the depth of this point is recorded. The depth at which rock is initially struck for a particular borehole will be recorded as part of the detail for that particular borehole survey. Once this has been recorded, the length of each sample is added to the depth as the details of each sample are logged. Depth measurements are incremental and are added automatically, unless core loss has occurred, when a new depth reference has to be entered.

The rod (15) is then moved on its slide (13) along the reference line (28) to where it intersects the plane of the structure (26) to be measured. The depth of this point is then automatically measured by the depth encoder (24) and recorded.

The first rotary encoder (11 ) is calibrated to the diameter of the core (4). A full rotation of the core represents 360 degrees. The β angle is then measured as the rotation angle between the reference orientation line (28) and the nose (31) of the ellipse (26).

It is the nose (31) towards the end of hole that is used for the measurements in this example. It will however be appreciated that the angles derived from the other, up the hole, nose will be complimentary and that the in situ strike and dip of the plane can equally well be computed from them.

The angular rotation required to bring the nose (31 ) into a vertical position, under the point of the depth rod (15), is measured and recorded as the β angle. This angle is measured between 0 degrees and 360 degrees. It is indicated in Figure 4 by showing the plane (32) through the nose of the ellipse (26) and core axis (26) relative to the vertical plane (30).

Note, once the depth measurement of the structural plane (26) has been entered, the depth encoder (24) is effectively switched off. The slide (13) can thus be moved to facilitate the measurement of the α angle, without affecting the depth measurement at all. The second rotary encoder (19) is provided to measure a 180 degree arc relative to the core axis (27). However, in the arrangement shown, the indicator (14) is zeroed when the cross bar linking its limbs (17) is lying flat on the rollers (7) to the left of the slide (13). The angle reading in this position is 8 degrees since the axis of rotation of the indicator (14) is below the rollers (7). This means that, in practice, no planar structure subtending an angle of less than 8 degrees relative to the core axis (27) can be measured by the indicator (14) of this machine (1).

The core (4) is rotated so the nose (31 ) of the ellipse of the structural plane (26) is in a vertical position on the roller bed (6) indicated by plane (32) in Figure 5. The limbs (17) of the indicator (14) are aligned with the ellipse of the structural plane (26). Once the indicator (14) is in position, the second rotary encoder (19) is used to record this angle as the α angle. The limbs (17) are parallel and planar. A structural plane (26) can be aligned with the plane defined between the limbs (17). This mitigates parallax errors in measuring the α angle. For the reason set out above, the inclination of the α angle can only be measured between 8 degrees and 172 degrees.

Planar structures can be either "open", where the core has fractured along the plane (34) as in Figure 6, or "healed" and contained within continuous core as the plane (26) is shown in Figures 4 and 5. Lineations (33) are occasionally found on the surface of such an open structural plane (34). In such a case, the in situ azimuth and plunge of the lineations (33) are computed by first measuring the β and α angles of the plane (34). The ellipse plane (32), which intersects the two noses, is then placed in the vertical position on the roller bed and the theta (θ) angle is measured as the rotation angle required to bring the lines of the lineation (33) into the vertical position, or parallel to the vertical plane on the roller bed.

The β, α and θ angles uniquely describe the attitude of planar and linear structures relative to the core axis. In combination with the borehole survey and the angle and position at which the hole was drilled, this information is used to construct a three-dimensional understanding of the subsurface rock structure. Structural data is collected as "point logs" in core, in that each data set is measured at a discrete depth, whereas lithological information is recorded over the interval that the rock type occurs. An overall "interval log" will be recorded for each core sample processed by the machine. Each interval log will include separate point logs, one for every geological structure on the core sample. All the data entries and the calibration of the encoders are thus recorded or effected using the computer (25).

Another embodiment of a core analysis machine (40) is shown in Figure 7. Most of the components of the machine (40) are the same as in the first embodiment (1 ) and will not be described further. However, this machine (40) is provided with a light source (41 ) to, in use, project a plane of light (42) onto the core sample (43). This arrangement replaces not only the α angle indicator (14) but also the depth rod (15) of the first embodiment (1 ).

More specifically, a variable strength light source (41 ) is pivotably mounted on an arm (44) connected to the depth slide (not shown). The slide runs on a guide (not shown) along the rear side of the frame (46). At least one suitable light emitting diode (LED) will be used as the light source (41 ). The source (41 ) includes a lens (not shown) suitable to project a narrow, planar beam of light (42) vertically down onto the core (43).

Rotation of the beam (42) is measured by using a rotary encoder (52) connected to a pivot pin (not shown) whereon the source (41 ) is mounted. The encoder (52) reads rotation of the beam (42) in a 0 degree to 180 degree plane referenced to the plane bisecting the rollers (51 ) and in which the axis (50) of the core extends.

The axis of rotation (48) about which the source (41 ) pivots is centrally located above the roller bed (49). It will be appreciated that this locates the source (41 ) directly above the axis (50) of a core (43) on the rollers (51) and with its axis of rotation (48) perpendicular thereto. This provides for the beam's axis of rotation (48) to intersect the axis (50) of a core (43) of any diameter laid on the rollers (51). This relative position is maintained along the full length of the core (43) as the beam (42) is moved along the roller bed (49). The axis of rotation (48) is no longer below the rollers and offset from the core axis.

An operator now has an entirely unobstructed view of the core (43) as it lies on the roller bed (49), with no mechanical indicator (14) in front of it. The plane of the beam (42) is easily aligned with the reference line (56) of the core (43). With the plane of the beam (42) rotated to project across the core (43) perpendicular to the core axis (50), as shown in Figure 8, it can be used to accurately measure the depth of the core sample (43) or of any structure along the core (43). In this manner, it can measure where the plane of the geological structure (54) intersects the core reference line (56).

Once the depth of the geological structure (54) has been measured, its attitude relative to the core axis (50), that is both the β and α angles, can be measured in one operation. Referring to Figure 9, both the structure (54) and light beam

(42) are rotated such that the plane of the beam (42) wraps around the core

(43) to lie exactly coincident with the plane of the structure (54). The rotations about the beta (core) axis (50) and the alpha (light beam) axis (48) necessary to bring the core (43) into this position measure the β(i) and α angles directly. The calculation of these two angles is shown more clearly in Figure 11 b).

The conventional β(2) angle [or β angle referred to with reference to the first embodiment and illustrated in Figure 4] can obviously also be measured if desired, using the light beam (42) - see Figure 11d). Both measurements uniquely describe the attitude of the structural plane (54).

It will be apparent that the attitude of a structural plane (54) sub-parallel to the core (43) can be measured with this embodiment of the machine (40). Measurement of the plunge of any lineation lying in the plane of an open fracture, or the theta (θ) angle, is likewise simply achieved either conventionally as shown in Figures 6 and 11c) or alternatively as shown in Figures 10 and As an alternative light source (41), a laser with a planar beam or a series of lasers arranged in a line on a suitably pivotable support can be used. A single centrally located laser can, in the case of the latter, be used on its own to operate as the depth marker.

The construction and design of the guide and slide arrangement of the machine (40) may be varied and such variations will be within the competence of a suitable skilled person. For example, the guide may be provided by an upright support along the rear of the roller bed (49) or by a structure spaced apart from and above the roller bed (49). What is important is that the optical indicator and marker of this embodiment are slidably supported for movement along and above the roller bed (49).

In the second embodiment of the machine (40) the depth slide is, unlike that of the first embodiment (1), not required to extend under and/or be supported at to the front of the roller bed (49). This allows for the frame (46) under the roller bed (49) to be properly supported along its length and to allow the length of the roller bed (49) to be extended in a modular fashion. In this way a roller bed (49) suitable for assembly of a length of core up to or in excess of 3 meters is provided. This allows for an entire core sample to be constructed on the roller bed (49) immediately as it is taken from the core barrel of a drilling rig. Next, the orientation line (56) can be accurately scribed along its length. Measurement of structure depths and angles and logging of the core lithologically etc. can take place before the sample is placed in core trays. In addition to the supports (55) for the frame (46), bearings (not shown) will be provided spaced apart along the length of the rollers (51 ), or on exposed axles between roller portions, to support the roller bed (49). Without proper support, the rollers (51 ) are forced apart by longer, and thus heavier, samples of core (43). Different arrangements to properly support a lengthened roller bed (49) will be within the design competence of a suitably skilled person.

It will be appreciated that a machine having a mechanical indicator (rather than an optical one) which pivots about an axis radial to, and preferably perpendicularly above, the axis of a core located on the roller bed will still have advantages even if it is not as convenient as the optical indicator second embodiment of the machine (40) to use. For example, a horizontal bar pivoting on such an axis will also enable the measurement illustrated in Figures 9 and 11b).

The core analysis machine according to this invention will also be provided with suitable video or other image recording equipment. The equipment will also be slidably mounted for movement along the roller bed. It may share a slide and/or a guide with the indicator already described. In addition to the measurements already mentioned, an image of the core will also be recorded by the machine. Image files of each sample can be compiled by recording the image of the core in longitudinal strips. This will then be available for follow up visual analysis at any time. The movement of the imaging equipment slide and the necessary rotation of the rollers can be an automated motorized operation.

The core analysis machine provides a solution to current core logging delays, inaccuracies and inefficiencies. It equips a geologist with effective means to comprehensively log the core on site at a rate that keeps pace with core production. In this way, a logging geologist's workplace is moved from the core- shed to the drill rig where he can now undertake all core preparation. He will also have full control of the quality of the core produced. A driller is then free to concentrate solely on producing continuous core from a bore that stays on target. The drilling charges can be standard, whatever the purpose of the programme.

The core analysis machine is rugged and manufactured for the direct field entry of logged data into a computer database. This method of logging core data on site at the drill rig, will not only improve core quality, but also markedly facilitate the process of ensuring that the full value of the drilling investment is achieved. The data is readily available for analysis in a matter of hours. In this way any inconsistencies, inaccuracies or malpractices can be identified and corrected well in time before they become an issue. The advantages in overall project quality control will be appreciated. The roller bed can also be adapted to measure the weight of a core sample. From this together with the diameter and length, the approximate density of a sample can be calculated. The machine can also include suitable equipment for measuring a variety of other physical properties of a core sample, such as, for example, magnetic susceptibility, natural gamma radiation, chemical composition, acoustic properties. Equipment for conducting spectral scans of the core, using near-infra-red or ultra violet light for example, may also be included. The motorized slide and guide arrangement suggested with respect to the imaging equipment can also be used for this equipment.

The computer which is enabled by suitable core analysis software and also provides the database into which the information is compiled may, as an alternative, be an embedded, dedicated feature of the machine, provided by suitable electronics. The machine will then also preferably include at least one suitable display screen. Data recorded onto such an "onboard" computer can be periodically downloaded.

Where the machine includes image and/or physical property recording equipment mounted for movement along the roller bed, the computer will preferably also be enabled by suitable controller software to operate the movement and functioning of the recording equipment.

It will be appreciated that instead of rotary encoders, electronic readers which monitor motion or position may be provided in any of a number of forms. The invention is thus not limited to using rotary or angle encoders and alternative encoders of the linear type, potentiometers, suitable transducers and sensors or other electronic measuring means or converters which can be calibrated as required and through which the required measurements can be converted to electronic readings will be within the design competence of a suitably skilled person.

It will further be appreciated that although the core analysis machine is primarily designed for logging data from diamond drilled rock core samples, in accordance with the method of this invention, it will readily, even if only on a limited scale, find application with core or cylindrical samples of materials other than rock. It may be used to measure some of the anisotropic properties, as well as describe the textures and features, of any solid cylinders of material, be they natural or synthetic.

Claims

1. A core analysis machine (1 ; 40) comprising a roller bed (6; 49) to rotatably support a core sample (4; 43) and an indicator (14; 41) pivotably secured to a slide (13) movable along a guide (12) parallel to the roller bed, with the roller bed having a roller (7; 51 ) connected to transmit rotation to a first electronic reader (11 ) and characterized in that the indicator is connected to transmit pivoting to a second electronic reader (19).

2. A machine as claimed in any of the preceding claims which includes a marker (15; 41 ) mounted on a slide (13) movable along a guide (7;51 ) parallel to the roller bed (6; 49) with the slide connected to transmit movement along the guide to a third electronic reader (24).

3. A machine as claimed in claim 1 or claim 2 in which the indicator (41 ) pivots about an axis (48) radial to the axis (50) of a core (43) located on the roller bed (49).

4. A machine as claimed in claim 3 in which the indicator (41 ) pivots about an axis (48) located centrally above the roller bed (49).

5. A machine as claimed in any one of claims 2 to 4 in which the indicator (14; 41 ) and marker (15; 41 ) are supported by the same slide.

6. A machine as claimed in claim 5 in which the indicator and marker are a light source (41) directed towards the roller bed (49).

7. A machine as claimed in claim 6 in which the light (42) is concentrated in a plane.

8. A machine as claimed in claim 1 in which the indicator (14) is a pair of parallel limbs (17), one on either side of the roller bed (6), connected at their free ends.

9. A machine as claimed in any of the preceding claims in which the electronic readers are respectively selected from the group comprising rotary encoders (11 ; 19; 24), linear encoders and potentiometers.

10. A machine as claimed in any of the preceding claims in which the roller bed (6; 49) is provided by a pair of elongate parallel rollers (7; 51) connected for synchronized rotation.

11. A machine as claimed in any of the preceding claims which is portable.

12. A machine as claimed in any of the preceding claims which is connectable to a computer (25) enabled by suitable core analysis software.

13. A machine as claimed in any of the preceding claims which includes image and/or physical property recording equipment mounted for movement along the roller bed (6; 49).

14. A machine as claimed in 13 which is connectable to a computer (25) enabled by suitable controller software to operate the recording equipment.

15. A method of logging rock core data comprising: removing a core sample from the core barrel of a drill rig; placing the core sample on a roller bed; and measuring and recording details of the core at the drilling site.

16. A method as claimed in claim 15 which includes marking the core with an orientation line when it is on the roller bed.

17. A method as claimed in claim 15 or claim 16 in which the details of the core are recorded on an electronic database.

8. A method as claimed in claim 17 in which the roller bed is that of a machine as claimed in claim 12.