TECHNICAL FIELD

[0001] The present invention generally relates to a sampling apparatus for collecting samples of drilled cuttings. In particular the present invention relates to a splitter assembly used in the sampling apparatus whereby the splitter assembly is capable of self-cleaning and provides a sample which is a better representation of the earth being drilled.

BACKGROUND ART

[0002] Drilling for geological samples is an important step in determining the location and feasibility of new sites for mining operations. Drilling is used in the mining industry to probe the contents of unknown and known ore deposits at potential sites.

[0003] A critical feature of assessing the feasibility of a potential mine site is the collection and analysis of geological samples. By withdrawing samples of rock and soil from specific depths, geologists can analyse the samples by chemical assay and conduct petrologic, structural, and mineralogical studies of the underground structures.

[0004] Drilling exploration is carried out to identify mineral resources with the view of identifying potential new mining sites. Drilling provides critical information for the evaluation of the mineral deposits in that area. Drilling is used to search for mineral occurrences or clues in the rocks that may lead to mineral deposits. Drilling penetrates deep into the ground and brings up samples. If there is any mineralisation at given points far beneath the surface, samples taken while drilling can quantify its presence at that particular point, and/or can indicate whether additional drilling is required/worthwhile in that area.

[0005] Mineral exploration is typically carried out in remote, harsh conditions. A drill rig is usually transported to a site and a drill team is used to run and maintain the rig. Existing exploration drilling rigs require skilled operators, often working in difficult and hazardous conditions. Noting the remoteness of most drilling locations, the drill team needs to be self- sufficient and be able to keep the rig running, as well as being able to look after themselves. This requires provision of fuel, water, spare parts, shelter and the essentials to live, namely water and food.

[0006] Drilling in any environment is hazardous but mineral exploration in remote locations, presents significant risk factors. As a result, there is a desire to move towards autonomous exploration drilling rigs, requiring less direct manual intervention during operation. [0007] Drill rigs can be set up for reverse-circulation drilling, rotary air blast drilling, wireline coring or open-hole boring. In reverse-circulation (RC) drilling, drill rods having two concentric tubes are used. Compressed air is supplied through the gap between the inner and outer tubes to act on a pneumatic reciprocating piston, known as a downhole hammer, comprising a drill bit with round protruding tungsten-carbide buttons that can cut hard rock. Drill cuttings are returned to the surface via the inner tube inside the drill rods.

[0008] At the surface, the cuttings are typically directed into a sampler. The sampler typically comprises a cyclone separator and a splitting device for dividing a sample from the cuttings. Samples of the cuttings are collected in order to later identify and/or assess the quality and quantity of the mineral the drill team are exploring. In light of the substantial costs associated with the establishment of a mine it is of significant importance that the samples taken are as true a representation of the drilled material as possible.

[0009] Typically the process of collecting samples involves passing a dirty gaseous stream (in which is entrained cuttings) through a cyclone separator. Generally the dirty gaseous stream enters tangentially near the top of the cyclone separator. As a result of the centrifugal forces, larger particles (cuttings) in the dirty gaseous stream are thrown to the sides of the cyclone separator and fall to the bottom, where they are collected or discharged through a bottom outlet. The remaining gas stream reverses direction and spirals up the center of the cyclone and out the top of the cyclone separator through a vortex finder.

[00010] As the gaseous stream circulates through the cyclone separator the cuttings fall to the bottom of the cyclone separator while the gaseous stream escapes from the top of the cyclone separator. A sample of the cuttings is then collected from a splitter at the cyclone’s outlet. The splitter seeks to provide an evenly distributed sample from the cuttings. Collection is largely a manual process where sample bags are filled from the cuttings at regular intervals. One of the drilling team takes the sample bags from the bottom of the cyclone separator, labels it and sets it aside for later collection and analysis. Typically a sample bag is taken from either side of the splitter and is taken at intervals dictated by the drilling program.

[00011 ] Several devices have been created to improve the sample taken from the drilled material leaving the cyclone. These devices seek to ensure the sample is a fair representation of the geological characteristics of the ground being drilled. One common device to improve the accuracy of the sample taken is a cone splitter. This type of splitter incorporates a cone which is located adjacent the outlet of the cyclone. As the cuttings impact upon the cone it is spread into an annulus from which the sample is taken. This device relies on an ‘hour glass’ effect between the cyclones outlet and the apex of the cone and is an area prone to blockages. [00012] An alternate device has a rotating cone and a port extending through the cone through which the sample passes. This device clogs when sticky and/or bulky cuttings are encountered as the port becomes blocked. In order to clear the blockage the splitter is required to be disassembled and cleaned.

[00013] Typically drilling exploration is carried out in dry environments. This, along with the drilling process, results in significant dust and airborne dirt. One way this may be minimised is to add water to the drilling process such that the cuttings returned to the surface are wet.

However, adding water to the process, or coming across sections of wet or damp earth, presents additional problems to the drill rig. In particular wet cuttings or clay based cuttings entering the system tend to clog the cyclone separator, the sampling assembly and the equipment downstream therefrom. This requires the drill team to clean the equipment and declog the material so that the equipment is able to run efficiently. This is time intensive and results in suspending the drilling process. In addition, when taking a sample, clogged material comprising material taken at different depths can dislodge and can fall into the sampler and enter the sampling bag at random intervals. This can contaminate/bias the sample and is not a fair representation of the rock being drilled at that point where the sample is taken.

[00014] As the drill team is on site, de-clogging the sampler is an everyday task and is one the team are readily able to complete. However, a drill rig which operates autonomously must find an alternate solution to maintain the equipment in functioning order while still ensuring a quality sample. Without this ability the sampler will become clogged, return biased samples and eventually stop operating.

[00015] The preceding discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.

SUMMARY OF INVENTION

[00016] It is an object of this invention to provide a splitter assembly which is capable of selfcleaning and provide a sample representative of the earth being drilled.

[00017] Throughout the specification the term ‘cuttings’ is used to describe material, which is caused to pass from a drilled hole, typically during the drilling process, into a sampling apparatus. These cuttings may be dry or wet and are typically delivered to the cyclone in a gaseous stream. [00018] Throughout the specification the term ‘dirty gaseous stream’ is used to describe a gaseous stream in which is entrained particulates, such as cuttings. The dirty gaseous stream may also contain fluid, such as water.

[00019] Throughout the specification the term ‘gaseous stream’ is used to describe a gaseous stream after previously entrained particulates, such as cuttings, have been removed. While the gaseous stream will have particulates removed therefrom, it is to be understood that the gaseous stream may not be completely free of particulates. The gaseous stream may also contain fluid, such as water.

[00020] Throughout the specification the terms cyclone generally refers to a device for removing particulates from a gaseous or liquid stream through vortex separation.

[00021] A sampling apparatus for use in extracting a sample from cuttings which are delivered to the sample apparatus from a drilling process, the apparatus comprises: a splitter assembly to mix the cuttings, the splitter assembly being capable of self-cleaning; a sampling assembly adapted to receive the cuttings from the splitter assembly and causing samples to be taken therefrom.

[00022] In one arrangement of the invention the cuttings are delivered to the sample apparatus entrained in a gaseous stream, wherein a separation means, such as a cyclone, separates the cuttings from the gaseous stream before passing to the splitter assembly.

[00023] In another arrangement of the invention the cuttings are delivered to the sample apparatus entrained in a liquid medium. This negates the need for a cyclone to separate the cuttings.

[00024] While the present invention is focused on embodiments where the cuttings are provided to the sampling apparatus entrained in a gaseous stream, in other embodiment the cuttings may be provided to the sampling apparatus a liquid medium. The splitter assembly of the present invention can operate where the cuttings are provided in either a gaseous medium, a liquid medium or a combination of both.

[00025] The splitter system may also be used with conventional drilling processes such as rotary mud drilling or rotary air drilling. [00026] The present invention provides a sampling apparatus for use in extracting a sample from cuttings which are delivered to the sample apparatus entrained in a gaseous stream, the apparatus comprises: a separation means to separate the cuttings from the gaseous stream; and a sampling assembly adapted to receive the cuttings from the separation means to allow samples to be taken therefrom, and a splitter assembly to deliver cuttings from the separation means to the sampling assembly wherein the cuttings are mixed and split to provide a substantially unbiased sample of the cuttings which is delivered to the sampling apparatus.

[00027] Preferably once the cuttings have passed through the splitter assembly the cuttings are mixed so that they provide an accurate representation of the geology of the earth from which the cuttings have been taken.

[00028] Preferably as the cuttings pass through the splitter assembly a predetermined portion of the cuttings are split from the cuttings and delivered to one or more sampling pots. In a typical arrangement approximately 8-14% of the cuttings may be delivered to one of the sample pot. This may be varied according to the sampling requirements.

[00029] Accordingly the invention further resides in a sampling apparatus for use in extracting a sample from cuttings which are delivered to the sample apparatus entrained in a gaseous stream, the apparatus comprises: a separation means to separate the drilled material from the gaseous stream a splitter assembly to mix the cuttings, wherein the cuttings exit the separation means and pass into the splitter assembly, the splitter assembly being capable of self-cleaning; a sampling assembly adapted to receive the cuttings from the splitter assembly and causes samples to be taken therefrom.

[00030] The splitter assembly may comprise a twin screw pump, wherein the twin screws intermesh. The screws may be in the form of a first rotor and a second rotor. [00031] The present invention provides a splitter assembly for mixing particulates, such as cuttings from a drill rig, the splitter assembly comprises: an inlet for receiving the particulates; a mixing region into which the particulates are received; a mixing means for mixing the particulates, and a sampling outlet from which a sample of the cuttings is channeled in an unbiased manner.

[00032] The mixing region may comprise the inlet, a shroud which contains the mixing region, and an outlet from which the mixed particulate dispenses from the mixing region.

[00033] The inlet of the mixing region may be adapted to be in fluid communication with a cyclone of a sampling apparatus from which the particulate is received.

[00034] The inlet of the mixing region may be adapted to be secured to an outlet of a cyclone of a sampling apparatus.

[00035] The mixing means may be housed in the mixing region.

[00036] The mixing means may comprise at least two rotors, wherein the rotors intermesh.

The at least two rotors may have flights which travel in opposite direction relative to each other. One rotor may comprise a left hand helix located on a shaft. The other rotor may be a right hand helix on an other shaft.

[00037] In one arrangement the thickness of each helix may increase as the helix travels from a first end to a second end of the helix.

[00038] In another arrangement the thickness of one helix may increase as the helix travels from a first end to a second end of the helix.

[00039] During operation the first end of the helix may be closer to a separator means, such as a cyclone, than the second end.

[00040] In another embodiment the mixing means may comprise more than two rotors, wherein the rotors intermesh.

[00041] In other embodiments the two or more rotors may have one or more helixes extending outwardly from a central shaft. The diameter of each of the two or more rotors may be uniform or may vary along the central axis. Each of the two or more rotors may have a different diameter to the other two or more rotors. [00042] In one aspect of the invention one of the rotors rotates around the other rotor.

[00043] In another aspect of the invention the rotors rotate about each other.

[00044] In one embodiment each rotor rotates about its own axis.

[00045] In another embodiment one rotor is fixed while the other rotor rotates.

[00046] In the preferable embodiment, one rotor is fixed, while the other rotor rotates about its own axis, and rotates about the fixed rotor. The fixed rotor does not rotate about its own axis. The fixed rotor may be located in a central position.

[00047] The rotors may rotate about an axis wherein the axis is parallel to the longitudinal axis of the mixing region.

[00048] The rotors may have a varying pitch whereby relative rotation of the rotors to each other seeks to scrape/clean any accumulated particulate therefrom. Preferably the rotors are continuously cleaned as they rotate.

[00049] The rotors may be orientated relative to the inlet such that as the particulate enters the mixing region the particulate first engages a top section of the rotors.

[00050] The mixing means may comprise a drive means for rotating the rotors, and/or rotating the rotors relative to each other. The rotational velocity of each rotor and/or the velocity at which they rotate with respect to each other can be varied according to various parameters including: the drill rate based on ground penetration rates, material type, water/moisture volume/ratio in the cuttings, mechanical wear rates, vibration induction, hydraulic efficiency, prevention of bias (where specific speeds results in discharge bias). .The drive means may comprise a motor and/or a plurality of gears to rotate the rotors.

[00051 ] The second rotor may rotate about the first rotor in a speed range of 0-300RPM. The speed may be determined/based on the above noted parameters.

[00052] The second rotor may rotate about the first rotor in a speed range of 0-200RPM. The speed may be determined/based on the above noted parameters.

[00053] The second rotor may rotate about the first rotor in a speed range of 0-100RPM. The speed may be determined/based on the above noted parameters.

[00054] Rotation of the rotors may be caused to slow or cease during specific drill rig events, such as rod change, maintenance. [00055] In one arrangement the motor is located below the outlet of the mixing region.

[00056] In another arrangement the motor is located to the side of the of the mixing region.

[00057] The drive means or a portion thereof may be protected by a housing to deflect particulate discharged from the mixing region away therefrom.

[00058] The outlet of the mixing region may provide one or more sampling stations. Each sampling station may receive and support a sampling pot, such that in use a portion of the cutting passing through the mixing region is channeled into the sampling pot in a substantially unbiased manner. The portion of the cutting being channeled to each sampling pot can be varied using an interchangeable die.

[00059] The splitter assembly adapted to co-operate with a sampling assembly wherein the sampling assembly feeds empty pots, and removes sampling pots with a sample, from each sampling station.

BRIEF DESCRIPTION OF THE DRAWINGS

[00060] Further features of the present invention are more fully described in the following description of a non-limiting embodiment thereof. This description is included solely for the purposes of exemplifying the present invention. It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out herein. The description will be made with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a sampling apparatus having a splitter assembly according to a first embodiment of the present invention;

Figure 2 is a front view of figure 1 ;

Figure 3 is a side perspective view of the splitter assembly shown in figure 1 ;

Figure 4 is a view similar to figure 3 having a shroud removed;

Figure 5 is a side view of the splitter assembly shown in figure 1 having the sampling pots removed;

Figure 6 is a cross sectional view of the splitter assembly shown in figure 5 through line AA;

Figure 7 is a top view of the splitter assembly shown in figure 1 ; Figure 8 is a bottom view of the splitter assembly shown in figure 1 ;

Figure 9 is a side view of a splitter assembly according to a second embodiment of the present invention;

Figure 10 is a cross sectional view of the splitter assembly shown in figure 9 through line AA;

Figure 11 is a cross sectional view of the splitter assembly shown in figure 9 through line CC;

Figure 12 is a top view of the splitter assembly shown in figure 9; and

Figure 13 is a cross sectional view of the splitter assembly shown in figure 12 through line BB.

[00061] In the drawings like structures are referred to by like numerals throughout the several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the present invention.

DESCRIPTION OF EMBODIMENTS

[00062] Referring to figures 1 and 2 , the invention according to the first embodiment is in the form of a splitter assembly 15 used in a sampling apparatus 13. The sampling apparatus 13 receives cuttings entrained in a gaseous stream from a drill rig (not shown), passes it through a cyclone 11 to separate the cuttings from the gaseous stream, before taking samples from the cuttings for analysis. In the present application the sampling apparatus 13 comprises the splitter assembly 15, the cyclone 11 and a sampling assembly 17.

[00063] The splitter assembly 15 receives the cuttings from the cyclone 11 . These cuttings are mixed in the splitter assembly 15 to aid in ensuring the sample is as accurate a representation of the drilled cuttings as possible, eliminating bias which may be induced by the cyclone 11 , the drilling process, the nature of the drilled material and/or the manner in which the dirty gaseous stream is delivered to the sampling apparatus.

[00064] The sampling apparatus 13 is adapted to be releasably secured to a drill rig (not shown). While the present sampling apparatus 13 is particularly designed to operate autonomously, such as on an autonomous drilling rig, it can also be readily integrated into existing drill rigs, and may be set up for manual or autonomous operation. [00065] Referring to figures 3 to 8, the splitter assembly 15 provides a mixing region 119 for receiving and mixing the particulates, being cuttings, from the cyclone 11 . The mixing region 119 comprises an inlet 121 through which the cuttings are received, an outlet 123 through which the cuttings pass as the cuttings leave the mixing region 119 and a shroud 125 which contains the mixing region 119.

[00066] The mixing region houses a mixing means which in the present embodiment is in the form of two rotors, a first rotor 127 and a second rotor 129. As best shown in figure 4, the rotors intermesh (only a portion of the helix of each rotor is shown).

[00067] The outlet 123 also provides two sampling stations 131 , into which is received a sampling pot 133. The sampling pot 133 is positioned to receive a portion of the cuttings dispensed through the outlet 123 before being removed for future analysis.

[00068] The mixing means comprises a drive means for rotating the rotors 127, 129. The drive means comprises a motor 135 and a set of gears 137 to rotate each rotor shaft 139 of the rotors 127, 129. In the embodiment shown the first rotor 127 rotates about an axis which is substantially co-axial with the axis of the inlet 121 , while the second rotor 129 rotates about the first rotor 127.

[00069] The motor 135 and gears 137 are located below the outlet 123 of the mixing region 119 and are protected from the particulate dispensed through the outlet, and not captured by the sampling pots 133, by a deflecting housing 141.

[00070] The rotors 127, 129 are sufficiently intermeshed and have a varying pitch whereby relative rotation of the rotors to each other scrapes/cleans any accumulated particulate therefrom, while minimising the likelihood of the rotors jamming relative to each other.

[00071 ] The rotors 127, 129 are orientated relative to the inlet 121 such that as the particulate enters the mixing region 119 the particulate first engages a top section 143 of each rotor.

[00072] In operation the cuttings from the cyclone 11 enter the mixing region 119 through the inlet 121. The rotating rotors 127, 129 mix the cuttings before the cuttings are channeled to the sampling pots 133. The splitter assembly 15 co-operates with the sampling assembly 117 wherein the sampling assembly 117 feeds empty pots 133, and removes sampling pots 133 with a sample, from each sampling station 131. [00073] The rotors rotate about a central axis of the mixing region at a sufficient speed such that the particulate is caused to engage the rotors as the particulate passes through the mixing region.

[00074] A splitter assembly according to a second embodiment of the invention is illustrated in figures 9 to 13. For convenience features of the second embodiment that are similar or correspond to features of the splitter assembly of the first embodiment have been referenced with the same reference numerals.

[00075] The second embodiment is very similar to that of the first embodiment with the exception of the drive means. In the second embodiment, a motor 235 of the drive means is located on the side of the mixing region 119. This results in a shorter splitter apparatus as well as placing the motor away from the outlet 123 of the mixing region. To accommodate the change in position of the motor the drive means comprises a different array of gears 237 to drive the rotors 127, 129.

[00076] Referring to figure 10, the thickness of the helix 275 on each rotor 127, 129 increases as the helix 275 approaches a second end 277 of the helix 275. As a result the distance between the helix of each rotor, once assembled and intermeshed, decreases as each helix approaches the second end 277. This decrease in distance assists in maintaining clean surfaces of the rotors. In addition, once assembled, the distance between the edge of the helix of one rotor and the shaft of the other rotor is such that build up of material on these surfaces is minimized.

[00077] The intermeshing of the rotors cleans the surfaces of the rotors to prevent clogging of the rotors and ensures the splitter assembly is able to effectively operate. The speed at which the rotors rotate about their axis, and relative to each other can be varied to accommodate different drilling parameters and sampling requirements.

[00078] In contrast to prior art, the present invention enables cleaning of the splitter assembly which minimises material build up and the likelihood of clogging and contamination of the collected sample. A problem with the prior art sampling systems is due to contamination resulting from build-up/caking which can occur on the surfaces. This is caused by variations in the cuttings which vary in consistency, particularly with cuttings which alternate from dry to wet to dry. This creates an environment for the cuttings to stick to the surfaces of the equipment. This is also the case with changes in the type of material being drilled which can vary in clay content, which are particularly sticky on surfaces. In the current invention the surfaces of the splitter assembly are cleaned to minimise the likelihood of buildup. [00079] Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the present invention. The present invention is not to be limited in scope by any of the specific embodiments described herein. These embodiments are intended for the purpose of exemplification only. Functionally equivalent products, formulations and methods are clearly within the scope of the invention as described herein. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

[00080] Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[00081 ] Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

[00082] Reference to positional descriptions and spatially relative terms), such as “inner,” “outer,” “beneath”, “below”, “lower”, “above”, “upper” and the like, are to be taken in context of the embodiments depicted in the figures, and are not to be taken as limiting the invention to the literal interpretation of the term but rather as would be understood by the skilled addressee.

[00083] Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[00084] It will be understood that when an element is referred to as being “on”, “engaged”, "connected" or "coupled" to another element/layer, it may be directly on, engaged, connected or coupled to the other element/layer or intervening elements/layers may be present. Other words used to describe the relationship between elements/layers should be interpreted in a like fashion (e.g., “between”, “adjacent”). As used herein the term "and/or" includes any and all combinations of one or more of the associated listed items.

[00085] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprise”, “comprises,” “comprising,” “including,” and “having,” or variations thereof are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

[00086] Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of possible implementations. In fact, many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of possible implementations includes each dependent claim in combination with every other claim in the claim set.