For many years, Priisk Solovyevsky, a Russian specialist in alluvial gold exploration, has relied mainly on excavators, bulldozers and loaders but now the company has invested in another way to recover the precious mineral – drill and blast.
Located in Solovyev in the remote Tynda district (Amursky province), the company was established as long ago as 1868 and has since produced around 220 tonnes of gold from 660 million cubic meters of alluvial mining territory.
Its current operation is a 145 year-old gold field that produces 2.2 tonnes of gold per year. However, despite its many years of success, Priisk Solovyevsky recognizes that new technology is the key to increase productivity in the shape of an Atlas Copco PowerROC D55 surface drill rig.
The mine has set a production target of for the new PowerROC D55 of one million tonnes of waste rock per year. Ivan Trubetskoy, who heads up the drilling department at Priisk Solovyevsky, says: “No matter what happens to the economy, gold mining is always regarded as a fundamental industry for growth and development in Russia.
Quality and reliability
“We bought the PowerROC D55 mainly for its high quality but also for its reliability, and that’s very important in this remote region with its low temperatures. In addition, the granodiorite ore in the pit has a compressive strength of 200 MPa so we need a powerful machine to drill it.”
Atlas Copco provided training for the operators and Atlas Copco Service maintains the rig and delivers the parts, although delivery times can sometimes be long due to the remote location.
Working two, 11-hour shifts per day, the PowerROC D55, which is equipped with the DHR6 H56 rotation unit, 114 mm rods and 130 mm spherical button bits, has so far drilled about 20 000 meters.
The benches are five meters high and the holes are drilled on a burden and spacing pattern of 3.5 x 3.5 m. The holes are drilled to a depth of 5 m with 0.5 m of subdrill. A total of 42 holes are drilled per shift and the rig gives an average penetration rate of 0.65–0.8 m/min depending on the rock, or 6.5 minutes per hole.
Emulsion explosives are used and bit grinding takes place after 380 meters of drilling.
The PowerROC D55
The PowerROC D55 is a high capacity drill rig for the hole diameter range of 110–165 mm (4 5/16’’– 6 1/2’’) and is designed for maximum uptime and simplicity of operation. It has an onboard compressor delivering 271.3 l/s of air up to a pressure of 20 bar and strong flushing, helping to ensure straight and clean holes. The straightforward hydraulic design delivers productivity and reliability in demanding applications and the high ground clearance and fast tramming ability provide high maneuverability in tough terrain.
Epiroc operated under the trademark “Atlas Copco” prior to January 1, 2018.