DRILLING PLATFORM FIELD OF THE INVENTION

The present invention relates to a platform on which machinery and other apparatuses can be operated. The invention has particular application as a platform on which geological sample drilling equipment can be located and operated. The invention is envisaged for use on land (as opposed to in the ocean), particularly in environmentally sensitive terrain. BACKGROUND TO THE INVENTION

Mineral exploration often requires the use of drilling equipment to extract core samples. This drilling equipment must be carefully positioned, in order for a quality sample to be obtained.

Generally, the drilling equipment, such as a drill rig, must be located on substantially flat terrain. This means that earth moving equipment must often be utilised to clear and level a space for the drill rig before it can be deployed. In addition, it may be necessary for a drill rig to be oriented in a number of directions (azimuths) in order that samples can be collected by drilling in a required orientation. The amount of cleared and levelled space must be sufficient to allow both reorientation, by manual or mechanical means, and operation of the drill rig.

Typically, drilling operations at a single site will require clearing of about 30m ² . Of course, samples will typically be taken at a number of sites in a particular area, and thus the total amount of clearing required will be several times this figure.

In an environmentally sensitive location, this degree of clearing is highly undesirable. In some cases, the degree of environmental sensitivity may mean that drilling can not be undertaken at all. In other cases, the problems of clearing land for drilling can require such additional regulation and oversight as to greatly impinge on the profitability of the exploration being undertaken.

The present invention seeks to provide a means by which drilling can be undertaken with a reduced environmental impact or 'footprint'. Other advantages and uses of the invention will become apparent from the following description. SUMMARY OF THE INVENTION

In accordance with a first aspect of the present invention there is provided a supporting structure for geological sample drilling equipment, the structure

comprising a platform on which geological sample drilling equipment can be positioned, and a plurality of legs, at least some of which are variable length, which support the platform above the ground, in use. Advantageously, this means that the drilling equipment can be located above the ground, thus obviating or at least reducing the need for ground disturbance and vegetation clearance beneath the drilling equipment. Preferably, all of the legs are independently variable in length.

When used on sloping or irregular terrain, the supporting structure might be most stably positioned in a particular angular configuration determined by the ground conditions. This angular configuration may not correlate to a desired angle for drilling. In a further aspect, the platform of the supporting rig includes a rotatable portion on which the drilling equipment may be positioned, the rotatable portion being able to rotate relative to the position of the legs. Preferably, the rotatable portion rotates about an axis substantially parallel to an elongate direction of the legs, that is, about a substantially vertical axis in use. This allows the drill rig to be angularly positioned (aligned) independently of the positioning of the supporting structure legs. The legs may thus be located to provide maximum stability to the platform, with the precise orientation of the drilling equipment to be determined by rotation of the rotatable portion of the platform. Further, drilling may occur at a number of locations about the supporting structure periphery, without the need for relocation of the legs.

Each leg may have more than one mechanism for varying its length. The legs may be modular, and be formed from a plurality of modules arranged to be coupled together in order to change the leg length by a discrete amount. Additionally, the legs may include a continuously variable adjustment means, such as feet which can be extended from or withdrawn into the legs by suitable means, such as hydraulic control. This allows the modules to be used to approximate the required leg length, and the adjustment means to be used for 'fine tuning' to provide the precise length required. In one embodiment of the invention, the leg modules are cylindrical sections including flanges at either end to allow coupling to adjacent modules. In an alternative embodiment, the legs may include a plurality of telescoping members.

Preferably, the platform has two parts, an annular fixed portion and a circular rotatable portion, located centrally within the annular portion. The annular fixed portion may be comprised in part by a plurality of independently removable sections. This allows a section to be removed to permit the use of drilling or other equipment between any removed section. The nature of the annular section allows flexibility of annulus size dependent on the level of confinement on a particular site.

In a preferred form, the supporting structure includes a substantially circular force transferring ring, on which the legs and annular portion are fixed and which supports the rotatable portion. The force transferring ring may include a track in which supporting rollers for the rotatable portion are located.

The rotatable portion may include releasable fixing means, such that when the fixing means is in a first position the rotatable portion is able to rotate relative to the fixed portion, and when the fixing means is in a second position the rotatable portion is restricted from rotation relative to the fixing means.

The supporting structure is preferably formed from a plurality of parts which may be connected by suitable means, such as bolting, whereby each of the parts can be carried manually. It is envisaged that the structure may be assembled on- site. It will be appreciated that the supporting structure can additionally provide a stable, horizontal and directionally variable mounting platform for other machinery, including operating as a fixed platform for landing helicopters. In accordance with another aspect of the present invention, there is provided a supporting structure for apparatus, the structure comprising a platform, and a plurality of legs, each of variable length, which support the platform above the ground, wherein the platform includes a rotatable portion on which the apparatus may be positioned, the rotatable portion being able to rotate relative to the position of the legs. The apparatus may, for instance, be geological sample drilling equipment, or it may be a helicopter. In accordance with a further aspect of the invention, there is provided a method of locating geological sample drilling equipment for use, the method including the steps of providing a supporting structure for the drilling equipment, the structure comprising a platform having a rotatable portion on which the drilling

equipment can be positioned, and a plurality of legs, each of variable length, which support the platform above the ground, locating the supporting structure such that the legs support the platform, positioning the drilling equipment on the rotatable portion, and rotating the portion such that the drilling equipment is oriented in a desired direction.

BRIEF DESCRIPTION OF THE DRAWINGS

It will be convenient to further describe the invention with reference to preferred embodiments of the supporting structure of the present invention.

Other embodiments are possible, and consequently, the particularity of the following discussion is not to be understood as superseding the generality of the preceding description of the invention. In the drawings:

Figure 1 is an upper perspective of a drilling equipment supporting structure in accordance with the present invention;

Figure 2 is a lower perspective of the drilling equipment supporting structure of Figure 1 ;

Figure 3 is a side view of the drilling equipment supporting structure of Figure 1 ; and

Figure 4 is a perspective of a supporting framework for a rotatable portion of a platform within the supporting structure of Figure 1. DESCRIPTION OF PREFERRED EMBODIMENT

Figures 1 to 3 show a supporting structure 10 which is arranged to support geological sample drilling equipment (not shown). The supporting structure 10 includes a circular platform 12 which is supported by four legs 14. The legs 14 are evenly spaced around a periphery of the platform 12. Referring to Figure 2, it can be seen that the key structural element of the supporting structure 10 is a substantially circular force transferring ring 16. In the embodiment of the drawings, the ring 16 is formed by two circular C-channel members, an inner member 18 having the channel opening inwardly with the web defining an outer diameter, and an outer member 20 having the channel opening outwardly, with the web defining an inner diameter. The respective webs of the inner and outer members 18, 20 are joined by suitable means such as bolts.

Each of the legs 14 is formed from a plurality of cylindrical modules 22. Each of the modules 22 has an upper flange and a lower flange, allowing

adjacent modules to be bolted to each other. The length of the legs 14 can thus be determined by the number and size of modules used to form leg 14. An upper module 22a of each leg 14 is fixed to the ring 16. A lower module 22b of each leg 14 has a foot 24 extending outwardly there from. Each foot 24 is mounted on a shaft 26 which is arranged to move under hydraulic power into or out of the respective lower module 22b. The effective length of the shaft 26 can thus be readily adjusted.

The platform 12 has two parts, a circular rotatable portion 30 and a fixed annular portion 32. The circular rotatable portion 30 includes a level surface 34 which is supported by a framework 36. The framework 36, best seen in Figure 4, includes a plurality of roller couplings 38 spaced about its circumference. The roller couplings 38 are arranged to receive rollers (not shown), which locate with a track defined by the ring 16 and permit rotation of the circular rotatable portion with respect to the ring 16.

The circular rotatable portion 30 also includes a releasable fixing means in the form of a plurality of brakes 40. The brakes 40 are mounted to the framework 36, and are selectively operable with the ring 16. When the brakes 40 are engaged with the ring 16, the circular portion 30 is restricted from rotating relative to the ring 16 and the legs 14. When the brakes 40 are not engaged with the ring 16, the circular portion can freely rotate relative to the ring 16.

The fixed annular portion 32 includes a level surface 50 which is co-planar with the level surface 34 of the rotatable portion 30, and which extends around the rotatable portion 30. The level surface 50 is secured to the ring 16 by means of a supporting framework 52. The supporting framework 52 includes a plurality of radial supports 54, with adjacent radial supports 54 connected by an outer connecting member 56. A level surface 50 is formed from a number of interlocking sections, with each portion of the level surface 50 being supported between adjacent radial supports 54 by a single connecting member 56. It is thus possible to remove a single section of the level surface 50 without affecting the remainder of the level surface 50.

In the embodiment of the drawings, each section corresponds to a 45° curvature of the annular portion 32.

In use, the supporting platform 10 may be assembled on site. Each of the components described above is formed from readily connectable parts, each of which can be carried manually.

In order to carry out a drilling operation at a desired site, an assessment is first made of the site in order to choose the most appropriate locations for the feet

24 to be firmly supported. Once these locations are determined, the legs 14 are each constructed such that the ring 16 connecting their upper modules 22a is substantially horizontal. This will require choosing a suitable type and number of modules 22 for each leg 14. In order to make the platform 12 perfectly horizontal, some hydraulic adjustment of each foot 24 within its lower module 22b may be required.

The platform 12 can then be assembled onto the ring 16, and drilling equipment placed upon the circular rotatable portion 30.

The rotatable portion 30 is then rotated to bring the drilling equipment to its desired angular position. This will involve the drilling equipment being directed to drill ostensibly through the fixed annular portion 32. In order to allow drilling to proceed, the relevant section of the annular portion 32 can be removed. Where drilling is required within the radius of the ring 16, a portion of the circular rotatable portion 30 may be similarly removed. Prior to drilling the brakes 40 may be engaged, to ensure that the platform

12 remains rigid.

When drilling at that location has been completed, the section of the annular portion 32 can be replaced, and the brakes disengaged. The rotatable portion 30 can then be rotated to bring the drill to another desired angular location, and the above process repeated.

It will be appreciated that drilling can therefore take place with the drilling equipment supported sufficiently highly from the ground that the only impact to the environment, other than where the drill is penetrating the ground, is beneath the feet 24. It is envisaged that this will reduce the local ground disturbing footprint from within the order of 30m ² to within the order of 1 m ² .

It will be appreciated that although the supporting structure has been described for use in relation to drilling, it may have other valuable uses. For instance, it may provide a landing site for a helicopter which is both safer and has

a smaller environmental impact than landing pads currently in use. Other uses and advantages will be apparent to a skilled user.

Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.