10.2.1 LDD SITE PREPARATION, RIG SET-UP AND DRILLING METHODS
The planning and site preparation of the LDD was carried out by Shore’s geological team. Actual LDD hole locations were established in the field, based on the geological core logging and interpretation of the quantitative data capture information obtained from the core holes. Collar co-ordinates were manually pegged in the field at a distance of approximately 2.0 m from the drill hole collar.
Once the location of the LDD sites were confirmed and inspected, the LDD drill rig and ancillary equipment was moved into place.
The Bauer BG-36 drilling rig was designed to carry out two methods/modes of drilling:
Kelly drilling; and
Air assisted fluid flush reverse circulation (“RC”) drilling.
The Kelly drilling mode consists of drilling/excavating overburden material with the use of Kelly bars and a bucket-like drill tool and hoisting the material up to surface. Whilst Kelly bar drilling approaches a depth of 40 metres, a 1.20 m diameter BV 1320 casing is emplaced. The Kelly drilling continues until it reaches its maximum depth of 85 m, at which depth the rig is converted to RC mode to continue the LDD hole to its completion.
10.2.2 LDD RC DRILLING AND SAMPLE RECOVERY DESCRIPTION
The Bauer BG-36 drilling rig is designed to carry out air assisted RC drilling, utilizing a drill string consisting of 6 metre-long dual walled drill rods, heavy weights (which provide downward pressure on the bit), stabilizers and a rotating drill bit assembly.
The RC drilling is assisted through the introduction of compressed air which is forced down through the outer annulus of the dual walled drill rods so as to assist the drill cuttings (“product”) and the mud in returning to the surface through the inner tube of the drill rods. The product then reports to the decelerating cyclone, which is located within a separate, adjacent Desander Plant (Figure 10.1). The discharge sample then exits from the cyclone and onto the coarse shaker screen for initial sizing at 3 mm.
The +3 mm size fraction and drill muds report to twin densifying cyclones and dewatering screens (nominal 0.85 mm) to separate the drill solids from the drilling mud/fluid. The drill solids (+0.85 mm) are then washed and report for sample collection while the drill muds (-0.85 mm) are reinstated and then returned downhole for recycling (Figure 10.2).
Sample material is collected in one cubic metre dual-walled, woven polypropylene bags, which are labelled, securely sealed then loaded onto a trailer for shipment to the secure storage area at the Star Diamond Project. The material is then processed through Shore's on-site process plant.
P&E Mining Consultants Inc. NI 43-101 Technical Report No 159 Shore Gold Inc. - Star Diamond Project Resource Estimate Update
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