Here is some more detailed information on what equipment is involved in drilling an exploration hole. See earlier blog posting for some photos.
Jolieske
DRILLING OPEN DAY REPORT – 14 JULY 2011
Everyone was a little shocked at the size of the three large vehicles that pulled into the grounds of the RS Hall last Thursday: there were two 15m semi-trailers and one 8tonne truck. However we were assured the semi-trailers were used only for major road repositioning, and that when the equipment was brought on site it would be on a large trucks. In addition two items (the drill rig and the rod handler) are on tracks (like a bulldozer) and can be “walked in” for a few kilometres if site access is tricky.
So for an exploration bore hole expect 3 large trucks (about 8 tonnes) each with a large piece of equipment which also weighs about 8 tonnes so total weight of each truck will be around 16 tonnes, plus a number of other vehicles and a trailer mounted pump.
One truck has the drill rig which is approx 2.2m x 4.3m and about 2.7m high when transported, 10.3m high when rig is vertical and working. Another truck has the rod handler which is approx 2.2m x 5.3m. Another truck has the sump which is 2.2m x 5.3m. This needs to be brought all the way to the site on the truck.
A trailer (2x6m) with large pump Up to four light vehicles for workers/supervisors/visitors A one-off delivery of 4,500 litres of water Removal of solid waste – stored in a skip and removed from the landholding for proper disposal Core samples are removed from the landholding and placed in purpose-built core trays and transported by light truck to a Centennial Coal storage facility.
The Site needs to be about 25m square, i.e. 25m x 25 m. It will be fenced off with chain link, same as you usually see around building sites (or other fence type as agreed with the landholder). The site needs to be level. Obviously the company prefers to do minimal site preparation, so will chose the flattest possible site, within meeting the JORC requirements of spacing of holes.
The Drill Rig is probably the smallest available that has the necessary capacity for this job and is state of the art. It also has the lowest ground bearing pressure of similar rig. It can be brought to the site on a flat-bed truck, and walked in on its own tracks for some kilometres. It needs to be positioned on a flat site, so cut and fill may be necessary if your site is sloping.
T
he Rod Handler is about same size and weight as the drill rig. It also is on tracks and can be walked in for a few kilometres. The rods are stored on the rodhandler during drilling and transport.
The Sump must be level. It is a closed fluid system which recirculates the water used in the drilling. Amount of water used is 4.500 litres per hole. The waste water and cuttings are pumped through a number of filters (the last is very fine) which take out all the particulates, up to 20 microns and the cleaned water is returned to the drill. The solid matter goes via a chute into a mini- skip (sort of size you might get in your yard). Skip will need to be emptied 2-3 times per hole. This of course depends on depth of the hole which will vary from a maximum of 270m to about 80m for the shortest.
Water: where possible this will be sourced on each property (subject to landholder agreement) after being analysed to ensure it is of adequate quality. This drill rig uses about half the amount of water of similar rigs. All engines are diesel and meet the highest emission standards (these are the European standards).
The drilling process The drill uses water when drilling unless it hits certain kind of ground conditions where it will be necessary to stabilise the ground. In this case a liquid polymer will be used. This chemical will viscosify the water i.e. makes the water thicker so that it doesn’t “melt the dirt” as the drilling progresses. The Material Safety Data (MSD) sheets for the chemicals use in the polymer will be made available. The chemicals are supposed to be fully biodegradable.
Occasionally it may be necessary to use a bit lubricant which is based on canola oil.
The drillers are specialist operators. The rig manager has over 20 years of experience in all parts of the world (but he will be managing, not actually operating the drill). It is a very high tech drill that can be remotely operated. It has a number of gauges which record what is happening and at what depth. An experienced driller can tell what is happening by listening to the flow of water being used in drilling and watching the speed at which the drill rotates. Theoretically then, we should be able to get a log of any water bearing layers encountered, showing the width of the layer and at what depth it occurs.
If the drill hits a water bearing layer they will stop and case the hole, then continue with a reduced bit size. If they hit too many water bearing layers (i.e. the bit size can only be reduced a certain number of times) they will stop, fill the hole, then start again in another place, starting out with a larger bit size so there are more opportunities to reduce the size.
They are obliged to have w licensed water driller if the hole is going to be kept open as a water monitoring bore. The siting of the drill hole and the drilling method has been developed with the assistance of a hydrogeologist. The basis for this is the recently completed water census. The consulting hydrogeologists are on call throughout the drilling program. Input of the hydrogeologists will be sought prior to, during and post each drill hole. The drillers and on-site geologists are trained and experienced in attending to any water issues during drilling and will always consult with the hydrogeologist.
Each site has to be inspected before drilling commences to be evaluated for archaeological, aboriginal and ecological factors. This may result in special requirements being put on the site. Each site will also be fully rehabilitated.
REF (Review of Environmental Factors) for the whole exploration process is being prepared for submission to the Dept for approval any day now.
Centennial indicated they may have another open day when the drill is actually set up on a site. There will be a second rig coming on line in about March or April next year. The first 26-28 holes cover stage 1 and 2, then Centennial decides on stages 3,4 and 5.
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