AU701081B2 - Drilling apparatus - Google Patents

Description

WO 97/02405 PCT/AU96/00421 1 TITLE: "DRILLING APPARATUS" FIELD OF THE INVENTION THIS INVENTION relates to drilling apparatus.

This invention has particular but not exclusive application to drilling apparatus for soil sampling and for illustrative purposes reference will be made to such application. However it is to be understood that this invention could be used in other applications such as for water drilling or installing ground anchors.

BACKGROUND OF THE INVENTION Soil sampling for mining exploration is typically carried out by drilling holes in the area to be explored and examining the material cut away by the drill. Various types of drilling apparatus and methods are used for this purpose such as diamond core sampling and reverse circulation rotatory and rotatory percussion sampling, open hole and reverse circulation down the hole hammer or top hammer, water jet, auger etc. Whilst these apparatii and methods offer a certain amount of satisfaction in homogeneous soils they have been found to be unreliable in recovering an accurate soil sample from heterogeneous soils such as coarse alluvials.

It has been found that contamination of the soil sample occurs due to scouring and cave-in of the exposed bore hole WO 97/02405 PCT/AU96/00421 2 walls by the fluids used for flushing as well as the influx of ground water and aquifer materials.

It has also been found that the presently available apparatus are subject to blockages of the flushing fluid passages, jamming of the drill string due to hole cave in, premature failure of drill tubes due to increased drilling torque requirements, all leading to an inability to recover a true representation of the vast variations in size and hardness of soil constituents.

It is a general object of the present invention to overcome, or at least ameliorate, one or more of the above disadvantages and to provide drilling apparatus which will be reliable and efficient in use.

SUMMARY OF THE INVENTION With the foregoing in view, this invention, in one aspect, resides broadly in drilling apparatus for soil sampling including:a rotary drive assembly; a cutter assembly operatively connected to said rotary drive assembly and including cutting means having a peripheral cutting edge; WO 97/02405 PCT/AU96/00421 3 fluid supply means adapted to supply flushing fluid to the vicinity of said cutting means; and fluid discharge means adapted to discharge flushing fluid from the vicinity of said cutting means.

Preferably, the outer cutter assembly is removably mounted to the end of a hollow rotary drive shaft which in turn is operatively connected to the drive assembly. It is also preferred that the cutting means includes an end portion having a concave recess formed therein and that the end portion has a cylindrical outer face adapted to cooperate with the wall of the hole as it is drilled to form a seal whereby flushing fluid is inhibited from discharging therebetween. Preferably, the recess is substantially conical or frustoconical and the wall of the recess provides an end face upon which cutting tools such as chisels or points may be mounted. In the preferred form, the hollow drive shaft is an outer shaft which forms the fluid supply means or fluid discharge means.

The apparatus may also include an inner cutter assembly for forming the core of the hole. Preferably, the inner cutter assembly is adapted for withdrawal from the hole independently of the outer cutter assembly whereby the seal WO 97/02405 PCT/AU96/00421 4 between the hole and the cylindrical face of the cutting means need not be broken in order to clear blockages in the fluid supply or fluid discharge means. It is also preferred that the inner cutter assembly is removably mounted to the end of an inner hollow rotary drive shaft encompassed by the outer hollow drive shaft and in turn is operatively connected to the drive assembly for synchronised driving with the outer cutter assembly. Preferably, the inner drive shaft is spaced radially from the outer rotary drive shaft to form an annular passage therebetween. It is also preferred that the inner cutter assembly includes a cutter head with an end face upon which cutting tools such as chisels or points may be mounted and has a central bore communicating with the hollow of the inner drive shaft and one or more flow passages provided about its periphery and communicating with the annular passage formed between the inner drive shaft and the outer drive shaft and hereinafter referred to as the "inner annular passage".

Preferably, the inner drive shaft forms the fluid supply means wherein flushing fluid is discharged centrally of the hole being drilled and the fluid discharge means is provided by the inner annular passage. However, the fluid supply means and the discharge means may be reversed although it is believed that such arrangement would be less efficient.

Alternatively, the passage between the outer drive shaft and IWO 97/02405 PCT/AU96/00421 the hole wall may be utilised as the discharge means if desired.

The apparatus may also include a casing assembly adapted to maintain the wall of the hole intact during drilling thereby preventing cave-ins and the ingress of soil and water to the vicinity of the cutting means and subsequently into the soil sample. In a preferred form of the invention, the casing assembly cooperates with the outer hollow drive shaft to provide an annular passage therebetween and hereinafter referred to as the "outer annular passage". In such an embodiment, the passage provides a flow path for the delivery of flushing fluid and other suitable drilling additives such as drilling mud to the cutting face.

In another aspect, this invention resides broadly in support apparatus for supporting a drill string extension assembly for a drilling apparatus as previously described, said extension assembly including an inner drive stem, an outer drive stem and a casing stem assembled in a telescopic arrangement, said support apparatus including: end engagement means for engaging the adjacent ends of the inner stem, the outer stem and the casing stem of said extension assembly; and WO 97/02405 PCT/AU96/00421 6 attachment means for attaching said support apparatus to said extension assembly.

Preferably, the end engagement means includes an inner stem engagement portion for slidingly engaging the end portion of the inner stem, an outer stem engagement portion for threadedly engaging the outer stem and a casing stem engagement portion for slidingly engaging the casing stem.

In such an embodiment, it is also preferred that the inner stem engaging portion includes prevention means for preventing rotation of the inner stem. In a preferred form of such an embodiment, the prevention means is a lug which engages with a complementary lug extending from the inner stem such as a vane provided on its outer face. Such apparatus allows the drill string extension assembly to be efficiently added to the down-the-hole drill string of the drilling apparatus.

Preferably, the attachment means includes an alignment means to maintain the extension assembly in a suitable lifting attitude wherein the upper end is hoisted prior to the lower end which is supported by the support apparatus. In a preferred form, the alignment means includes a clamp which circumscribes the upper end portion of the casing stem and is maintained in a spaced apart relationship with the end 1 WO 97/02405 PCT/AU96/00421 7 engagement means by an attachment means such as a hoisting bar or cable.

In another aspect, this invention resides broadly in a collection apparatus for the collection of drill cuttings from soils including: a plurality of longitudinally extending body parts adapted for assembly to form a tubular body; and holding means for holding said body parts in the thus assembled attitude.

Preferably, the body parts are two opposed complementary members each of substantially semi-circular cross section.

Preferably, the collection apparatus also includes closure means for closing at least one end of the tubular body when in the assembled attitude.

More preferably, such closure means close each end of the tubular body when in the assembled attitude.

In another aspect, this invention resides broadly in a method of collecting drill cuttings from soils including: WO 97/02405 PCT/AU96/00421 8 providing collection apparatus as previously described; and delivering said drill cuttings to said apparatus in cutting sequence.

Preferably, the apparatus is arranged to receive the drill cuttings as they are discharged from the drilling apparatus.

For this purpose, a plurality of collection apparatus as previously described may be provided in a carrier whereby individual apparatus may be filled sequentially thereby allowing a continuous drilling log to be maintained.

Preferably, the apparatus is placed in a substantially vertical orientation for filling from an upper end thereof and the upper end is capped upon filling such that the order of cutting is mimicked in the order of sample material in the apparatus.

The apparatus may be placed horizontally for removal of one or more body parts to enable inspection and logging of the drill cuttings. Furthermore, a smaller representative sample may be removed and maintained in cutting sequence by removal of a longitudinal body part.

WO 97/02405 PCT/AU96/00421 9 DESCRIPTION OF THE INVENTION In order that this invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherein: Fig. 1 is a pictorial representation of a drilling apparatus according to the invention.

Fig. 2a is a sectional elevation of the upper part of the drilling assembly of the apparatus of Fig. 1.

Fig. 2b is a sectional elevation of the lower part of the drilling assembly of the apparatus of Fig. 1.

Fig. 3 is a bottom view of the cutter assembly of the apparatus of Fig. 1.

Fig. 4 is a sectional plan of the separating chamber of the apparatus of Fig. 1.

Fig. 5 is an elevation including sections of various components of an extension assembly according to the invention.

WO 97/02405 PCT/AU96/00421 Fig. 6 is a sectional elevation of a sampling apparatus according to the invention.

Fig. 7 is a plan view of a sampling tube as illustrated in Fig. 6 in a tube holder and ready for inspection.

Fig. 8 is an elevation of the holding apparatus of Fig. 7 in the discharging position.

Fig. 9 is a sectional elevation of an inner stem coupling arranged to seal the inner annular passage of the apparatus of Fig. 1.

Figs 10, 11 and 12 illustrate the procedure for inserting the extension assembly of Fig. 5 in the drill string of the apparatus of Fig. 1.

The drilling apparatus 10 illustrated in the drawings includes a drill assembly 11 which is driven by a rotary percussion drive assembly 13 slidably mounted on a feed beam 14. At its upper end the drill assembly has a head assembly 12 which is slidably mounted on the feed beam 14 also. At its lower end the drill assembly includes a cutter assembly The drill assembly may be raised and lowered by a cable and pulley arrangement including a pulley mounted on the feed WO 97/02405 PCT/AU96/00421 11 beam and a pulley mounted on the head assembly as is well known.

The cutter assembly includes an inner cutter head 16 which is slidably located in the bore 17 of an outer cutter head 18.

An inner drill stem assembly 19 extends upwardly from the cutter head 16 and comprises hollow inner drill stems coupled together to form a flow passage 20a by complementary hollow inner drill stem couplings 23. The inner cutter head is threadedly connected to the lowermost inner drill stem which includes circumferentially spaced centralising members extending radially outwardly for maintaining the stem centrally of the outer drill stem assembly to be described hereinafter. The uppermost inner drill stem 21 extends upwardly beyond the head assembly 12 and includes a socket 22 which is threadedly coupled to the hollow spigot of the drive assembly 13 for rotation therewith. A hose 22a is connected between the spigot and a flushing fluid supply pump (not shown) whereby fluid may be supplied to the cutter assembly via the flow passage The outer cutter head 18 is threadedly connected to an outer drill stem assembly 24 which circumscribes the inner drill stem assembly and forms an inner annular passage therebetween. The outer drill stem assembly 24 comprises a plurality of hollow outer drill stems 26 connected by WO 97/02405 PCT/AU96/00421 12 complementary hollow outer drill stem couplings 27. The uppermost outer drill stem 28 also extends upwardly beyond the head assembly 12 and includes a percussion transfer boss 29 of a castellated form which engages with a complementary castellated boss 31 provided on the end portion of the uppermost inner drill stem 21 for receiving the rotary force and percussive impulse from the drive assembly 13 via the upper most inner drill stem 21.

A casing assembly 32 comprising engaged casing stems 33 having complementary reverse threaded socketted and spigotted ends circumscribes the outer drill stem assembly 24. The socket of the lowermost casing stem threadedly receives a removable bearing assembly 36 (described hereinafter) in which the outer cutter head 18 rotates. The upwardly extending spigot 37 of the uppermost casing stem engages with the complementary internal thread of the socket end of an adaptor 35. At its upper end the adaptor has a spigot which is externally threaded in a forward direction and engages the complementary internal thread of a casing end cap 38. The adaptor 35 is adapted for rotation by a suitable tool 34 which is used to disengage it from the uppermost casing stem and the casing end cap 38 at the same time.

The head assembly 12 includes a saddle 53 which slidably engages with the feed beam 14. A lifting beam 54 extends WO 97/02405 PCT/AU9600421 13 outwardly from the upper end portion of the saddle and includes an aperture 55 housing a hoisting bush 56 through which the inner and outer drill stem assemblies pass. A lifting ram 57 is connected between the lifting beam 54 and the end cap 38 which in its operative position is directly below the lifting beam and is operative to raise and lower the end cap to allow the inclusion of additional stem extension assemblies as described hereinafter.

The end cap 38 has a longitudinally extending sleeve portion 39 in which the upper most outer drill stem 28 is slidably received and which provides an inner cylindrical bearing surface 41 for rotation of the uppermost outer drill stem 28 relative thereto. An 0-ring or gland seal 42 is provided in the sleeve for preventing the flow of fluid between the outer drill stem 28 and the end cap. Rotation of the end cap 38 with the outer drill stem assembly 24 is prevented by engagement of a spur tooth 44 which extends from the outer face of the end cap and slidingly engages in a complementary longitudinally extending groove 59 formed in the saddle 53.

The outer drill stem coupling 27 is cylindrical in cross section and is rotatably received in the casing spigot 37 of the upper most casing stem 40. A clearance passage 27a provided about the coupling 27 allows flow of flushing fluid and other additives such as drilling mud from the inlet 49 to WO 97/02405 PCT/AU96/00421 14 the outer annular passage 43 formed between the casing stems and the outer drive stem assembly.

The outer cutter head 18 includes an upper cylindrical mounting portion 61 and a lower cutting portion 62 which extends radially beyond the mounting portion 61. The mounting portion 61 includes an upwardly opening socket which threadedly receives the complementary spigot of the lowermost outer drill stem as previously described and is rotatable therewith. The mounting portion 61 is rotatably mounted in the removable bearing assembly 36 which has a housing 63 threadedly secured in the socket end of the lower most casing stem via a spigot portion 65 provided at its upper end. At its lower end the housing has a socket 64 which houses a replaceable bearing member 66. The end face of the spigot portion 65 provides a shoulder 67 against which a retaining ring 60 mounted in a groove 68 provided in the upper cylindrical mounting portion 61 of the outer cutter head may rest thereby ensuring that the casing assembly 32 moves longitudinally downward with the cutter head as the hole is drilled. A seal 69 is provided in a groove formed in the inner face of the housing 63 for sealing against the outer cylindrical face of the upper cylindrical mounting portion 61 thereby preventing the ingress of out-of-hole fluids and ground water to the outer annular passage 43 particularly WO 97/02405 PCT/AU96/00421 when the hole is depressurised, such as whilst an extension assembly is being added to the drill string.

The lower cylindrical drilling portion 62 of the outer cutter head 18 includes a frustoconical recess 70 in its lower end face which provides a frustoconical mounting surface 71 upon which radially extending drilling chisels 72 are mounted.

Additionally, a circumferentially extending drilling chisel 73 is secured in a circumferential recess provided in the outer face of the lower cutting portion 62 and aligns with it.

The inner cutter head 16 includes a boss 76 at its lower end and a spigot 77 extending upwardly therefrom which threadedly engages with the lowermost inner drill stem 25 as previously described. A bore 75 is provided in the cutter head and provides a flow passage between the passage 20a provided by the inner drill stems 21 and the frustoconical recess 70 for the supply of flushing fluid thereto. Three circumferentially spaced vane-like centralising members 78 extend outwardly from the boss 76 to positions of close proximity to the cylindrical wall of the bore 17 provided in the outer cutter head 18. The vanes 78 and the bore 17 cooperate to form discharge flow passages 79 between the frustoconical recess 70 and the inner annular passage whereby flushing fluid may be discharged from the WO 97/02405 PCT/AU96/00421 16 frustoconical recess upwardly through the inner annular flow passage 30. The flow passages 79 expand away from the frustoconical recess 70 so as to provide a self cleaning action to reduce clogging during drilling.

The outer cutter head 18 includes a plurality of circumferentially spaced flow passages 74 which extend from the frustoconical face upwardly through the cylindrical mounting portion 61 to the outer annular passage 43 and provide a flow path by which flushing fluid and other additives may be supplied to the cutting surface.

The upper end of the uppermost outer drill stem 28 includes a boss 82 having an annular shoulder portion 83 which is supported by the hoisting bush 56 provided in the lifting beam 54. A transfer chamber casing 86 circumscribes the boss and forms a transfer chamber 87 adapted to receive the flushing fluid and entrained cuttings from the passage The boss 82 forms an impeller comprising three upwardly spiralling vanes 84 which terminate in three circumferentially spaced radially extending ports 84a respectively which are axially aligned with the inlet to the transfer chamber 87. The impeller assists in forcing the drill cuttings radially into the transfer chamber. The vanes 84 also impart some tangential velocity to the cuttings so that build-up in the upper part of the annular passage 30 and WO 97/02405 PCT/AU96/00421 17 in the transfer chamber is prevented. The transfer chamber is maintained in its position about the boss 82 by a clamp which engages in a groove extending circumferentially about the boss and also in a groove extending circumferentially about the transfer chamber. A delivery hose 89 extends between the transfer chamber 87 and the separating apparatus 200 (described hereinafter) spaced from the drilling apparatus and provides a flow passage for flushing fluid thereto.

In use, the drill assembly 11 is percussed and rotated by the drive assembly 13 so that the cutter assembly 15 drills a hole in the ground to be tested.

Flushing fluid is supplied to the cutter assembly 15 through the flow passage 20a provided by the inner drill stem assembly and the flow passages 43 provided between the outer drill stem assembly and the casing stem assembly in order to flush the cuttings to the surface for testing. In the embodiment illustrated the flushing fluid utilised is air but in other embodiments other fluids such as water or slurry could be utilized.

The flushing fluid enters the frustoconical recess 70 through the bore 75 formed in the inner cutter head 16 and the passages 74 formed in the outer cutter head and passes WO 97/02405 PCT/AU96/00421 18 between the frustoconical end face of the outer cutter head and the hole end picking up the cuttings of soil and rock which have been removed from the hole end by the inner and outer cutter heads 16 and 18 respectively. The flushing fluid is discharged from the frustoconical recess through the discharge flow passages 79 and it then flows upwardly through the inner annular flow passage 30 to the transfer chamber 87 from where it is discharged to the sampling apparatus 200.

Advantageously the outer cutter head 18 prevents the flushing fluid from impinging on the cylindrical wall of the hole adjacent the lower cutting portion 62 of the outer cutter head 18 thereby preventing erosion of the hole wall and undesirable mixing of wall soil with the cuttings. The cone angle of the frustoconical recess in this embodiment is approximately 90 degrees but it is believed that the angle is best selected between 20 degrees and 120 degrees depending on soil or rock type to be tested.

The position of the inner cutter head 16 relative to the outer cutter head 18 may be varied by adjusting the relative lengths of the inner and outer drill stem assemblies. This may be achieved by selecting inner or outer drill stem couplings of different lengths. It has been found that the apparatus is most effective if the inner cutter head 16 protrudes beyond the bore 17 of the outer cutter head by no more than WO 97/02405 PCT/AU96/00421 19 Drilling mud and other drilling additives hereinafter referred to simply as "drilling mud" are supplied to the cutter assembly 15 by a mud pump (not shown). The drilling mud enters the outer annular passage 43 through the flushing fluid inlet 49 in end cap 38 and flows downwardly to the upper end face of the outer cutter head 18 with the flushing fluid where it accumulates. The mud is forced radially outwardly by the pressure of the flushing fluid in the annular passage 43 and exits between the one-way seal 69 and the bearing member 66. The mud accumulates on the wall of the hole thereby sealing it so as to prevent the ingress of ground water to the vicinity of the cutter heads. The mud also inhibits the escape of flushing fluid externally of the outer cutter head.

The inner stem coupling 23a illustrated in Fig. 9 may be utilized to seal the inner annular passage 30 if necessary in order to utilize the flushing fluid supply to assist in withdrawing the drill stem assembly 11 from the hole. In order to seal against the inner wall of the outer drill stem assembly the coupling includes a central flange portion 23b which extends outwardly from the stem coupling portion and includes an 0-ring 23c mounted therein.

WO 97/02405 PCT/AU96/00421 The extension assembly 110 illustrated in Fig. 5 includes an inner stem 111, an outer stem 112 and a casing stem 113. The upper end of the inner stem includes an inner stem coupling 116 screwed therein and adapted to engage with the complementary socket of the uppermost inner drill stem 21.

However, the inner stem coupling could be included at the lower end of the inner stem if desired. Similarly the upper end of the outer drill stem 112 includes a socket 117 adapted to engage with the spigot end of the upper most outer drill stem 28. The upper end of the casing stem 113 is spigotted and is threaded so as to engage with the adaptor 35 as previously described. The extension assembly is supported by a support apparatus 121 which includes an end engaging part 122 for engaging the lower end of the extension assembly, a clamping bracket 123 for clamping about the upper end portion of the casing stem 113 and a hoisting cable 124 for connecting the clamping bracket and the end engaging part. A lifting cable 125 is attached to the clamping bracket 123 and is moveable by a winch or like mechanism located on the feed beam to raise the extension assembly.

The end engaging part 122 includes a base portion 126 from which an upstanding wall 127 extends to form a socket 127a.

The wall is internally threaded so as to threadedly engage with the lower end of the outer stem 112. A hob 129 also extends upwardly from the base portion 126 concentrically WO 97/02405 PCT/AU96/00421 21 with the socket wall 127 and spaced inwardly therefrom for engagement with the lower end of the inner stem 111. The hob includes a relieved upper portion which forms a spigot 131 for sliding engagement in the threaded bore of the stem 111 and a shoulder 132 which abuts the end of the stem and maintains it in the desired longitudinally spaced relationship with the outer stem 112. A lug 133 is provided on the hob 129 and extends parallel to the spigot 131 and spaced radially from it for engagement between the vanes 125a (corresponding to vanes 25a) provided on the inner stem 111 thereby preventing rotation of the inner stem relative to the outer stem.

A cylindrical wall 136 circumscribes the socket wall 127 and forms a further socket 137 for slidingly receiving the lower end of the casing stem 113 therein and maintaining it in the desired longitudinally spaced relationship with the outer stem assembly 112. A lug 139 extends outwardly from the base portion and includes an aperture 140 which pivotally receives a complementary cable end connector 141.

The clamp 123 circumscribes the upper end of the casing stem 113 and is slidably removable therefrom upon release of the clamp in the known manner. The clamp is pivotally attached to the other end of the cable 124 in a manner similar to that described in relation to the other end.

SWO 97/02405 PCT/AU%6/00421 22 In order to add an extension assembly to the drill string the support apparatus is connected to the extension assembly as previously described and the extension assembly is raised to the desired position above the down-the-hole drill string.

It will be appreciated that the upper end portion of the inner stem 116 protrudes beyond the upper end of the outer stem 112 and the casing stem 113 making it clearly visible to the drill operator wherein it may be aligned with the exposed upper most inner drill stem 21 as illustrated in Fig. 2. The outer drive stem 112 is then aligned with the exposed uppermost outer drill stem 28 and coupled by rotating the drive assembly in the forward direction whilst the outer drive stem extension 112 is prevented from turning by the hoisting apparatus 121. The adaptor 35 may be then lowered into contact with the casing stem extension 113 and the extension stem may be rotated with a pipe wrench thereby connecting the casing stem 113 to the socket end of the adaptor 35. In order to prevent the adaptor 35 rotating with the casing stem extension 113 the lugs 35a extending from the adaptor are arranged to engage with the flanges forming the walls of the groove 59.

The casing tube extension 113 may be then supported by the lifting ram 57 and the inner and outer drill stems may be supported by the lifting beam 54 such that the support WO 97/02405 PCT/AU96/00421 23 apparatus 121 can be disconnected from the extension assembly.

After removal of the support apparatus 121 the lower ends of the inner stem, outer stem and casing stem 111, 112 and 113 respectively may be connected to their respective drill strings. Subsequently the drive assembly may be rotated in a forward direction to tighten all of the joints.

The sampling apparatus 200 illustrated in Figs 6, 7 and 8 includes an inverted cone 211 which is arranged in the known manner to receive flushing fluid and the entrained drill cuttings from the discharge hose 89. The sample cuttings are discharged through the lower end of the cone into a sampling tube 213. Two sampling tubes 213 and 214 are supported on a trolley 215. The tube 213 has its upper end open and positioned beneath the lower discharging end of the cone 211.

Upon filling of one of the sampling tubes the trolley is moved such that the other sampling tube is positioned under the cone for filling. The full sampling tube is then capped and removed for logging and replaced with another empty tube and so on.

The sampling tube 213 comprises two opposed complementary tube halves which are clamped together by a plurality of clamps (not shown) of any suitable form such as rubber rings WO 97/02405 PCT/AU96100421 24 or bolted clamps and have a bottom end cap and a separate top end cap.

The full sample tubes may be inspected after being laid horizontally. The upper tube half is removed wherein the contents 216 may be inspected for logging. It will be appreciated that the contents of the tube will be substantially in sequential order as cut by the drilling apparatus. After logging the drill cuttings contained in each tube may be bagged for testing purposes. Bagging may be achieved easily by simply pivoting the tube holder 217 about its pivot pin 218 so that the sample may flow into the bag 219 as illustrated in Fig. 8 after removal of the end cap 220.

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 the invention as defined in the following claims.

Claims (23)

1. 2. Drilling apparatus according to claim 1, wherein said cylindrical outer face is adapted to form a seal with the wall of the hole being drilled whereby flushing fluid is inhibited from discharging between said outer face and said wall.
2. 3. Drilling apparatus according to claim 1 or claim 2, wherein said inner drive stem is hollow and said hollow forms part of said fluid supply means.
3. 4. Drilling apparatus according to claim 3, wherein said inner drive stem and said outer drive stem form therebetween an inner annular passage which forms said fluid discharge means.
4. 5. Drilling apparatus according to claim i, wherein said inner cutter assembly can be withdrawn from the hole being drilled independently of said outer drive stem.
5. 6. Drilling apparatus according to claim 1, wherein said inner cutter assembly is rotatable in said bore.
6. 7. Drilling apparatus according to claim i, wherein said inner stem and said outer stem are connected to said rotary drive assembly for synchronised driving.
7. 8. Drilling apparatus according to claim 4, wherein fluid flow passages are provided between said inner cutting means and said inner annular passage for discharge of flushing fluid from said /t9601032.wpd Z AMENDED SHEET 'PFA/ALJ pCT/AU T 0 0 4 2 1 RECEIVED 1 1 MAR IS97 -27- inner cutting means.
8. 9. Drilling apparatus according to claim 8, wherein said inner cutter head includes a plurality of vanes extending radially from a central hub, said vanes in cooperation with said bore forming said flow passages. Drilling apparatus according to any one of claims 1 to 9 and further including a casing assembly adapted to maintain the wall of the hole intact during drilling.
9. 11. Drilling apparatus according to claim 10, wherein the casing assembly cooperates with the outer- drive stem to provide therebetween an outer annular passage.
10. 12. Drilling apparatus according to claim 11, wherein said outer annular passage provides a flow path for the delivery of flushing fluid and drilling additives to said outer cutting means.
11. 13. Support apparatus for supporting a drill string extension assembly for a drilling apparatus according to any one of claims 1 to 12, the extension assembly including an inner drive stem, an outer drive stem and a casing stem assembled coaxially, the support apparatus including: end engagement means for engaging the adjacent ends of the inner stem, the outer stem and the casing stem of said extension assembly; and attachment means for attaching said support apparatus to said t9601032.wpd AMENDED SHEET IPEA/AL pcr.u9 6 0 0 4 2 1 C? JIEJ1 tj 57 -28- extension assembly.
12. 14. Support apparatus according to claim 13, wherein said end engagement means includes an inner stem engagement portion for slidingly engaging the end portion of said inner stem, an outer stem engagement portion for threadedly engaging said outer stem and a casing stem engagement portion for slidingly engaging said casing stem.
13. 15. Support apparatus according to claim 14, wherein said inner stem engaging portion includes prevention means for preventing rotation of said inner stem.
14. 16. Support apparatus according to claim 15, wherein said prevention means includes a lug which engages with a complementary lug extending from said inner stem.
15. 17. Support apparatus according to any one of claims 13 to 16, and further including alignment means for maintaining said extension assembly in a suitable lifting attitude wherein said upper end is hoisted prior to said lower end which is supported by said support apparatus.
16. 18. Support apparatus according to claim 17, wherein said alignment means includes a clamp which circumscribes said upper end portion of said casing stem and is maintained in a spaced apart relationship with said end engagement means by attachment means. /t9601032.wpd AMENDED SHEET 'P-A0U PCr/AU G 0 0 4 2 1 -29-
17. 19. Support apparatus according to claim 18, wherein said attachment means is a hoisting bar or cable.
18. 20. Collection apparatus for collecting drill cuttings from soils including: a pair of complementary body parts of substantially semi-circular cross-section adapted for assembly to form a tubular body, one of said body parts having fixed thereto bottom end closure means for closing one end of the tubular body; holding means for releasably holding said complementary body parts assembled, and removable closure means for closing the other end of the tubular body, said removable closure means being adapted to engage within the tubular body so as to abut drill cuttings contained therein, the apparatus being so made and arranged that the other of said complementary body parts may be removed to allow inspection of the drill cuttings when in a horizontal attitude.
19. 21. A method of collecting drill cuttings including: providing collection apparatus having a pair of complementary body parts of substantially semi-circular cross-section adapted for assembly to form a tubular body, one of said body parts having fixed thereto bottom end closure means for closing one end of the tubular body; assembling said tubular body parts to form a tubular body and releasably securing said complementary body parts in the assembled attitude and standing said assembled tubular body in a substantially upright attitude; delivering drill cuttings to said collection apparatus in cutting sequence, and closing the other end of said tubular body with removable closure means.
20. 22. A method according to claim 21, including fitting said removable closure means within said tubular member and compressing the drill cuttings so as to form a solid cylinder of therein.
21. 23. A method according to claim 22, wherein said collection ejA 1 apparatus is arranged to receive drill cuttings as they are 3 9AME6' OZD SHEET E.A /^'IL RECEIVED D .<T discharged from a drilling apparatus.
22. 24. A method according to claim 23, including providing a plurality of said collection apparatuses in a carrier whereby individual apparatus may be filled sequentially thereby allowing a continuous drilling log to be maintained. A method according to claim 24, including placing said collection apparatuses in an upright orientation for filling via an upper end thereof and capping said upper end of each collection apparatus upon filling such that said order of cutting is mimicked in said order of sample material in said apparatus.
23. 26. A method according to claim 24, including placing one of said collection apparatuses in a substantially horizontal attitude for removal of one or more body parts to enable inspection and logging of said drill cuttings. IA V_77 SHEET 0' J)P VAU