Goldcorp (TSX: G; NYSE: GG) has been so growth-oriented over the past decade. In 2015 Goldcorps. Inc focus mining exploration on the discovery of high grade HG Young at the Red Lake mine. And in the Campbell Complex red lake gold mining district is completed underground drilling has commenced and will continue throughout 2015. Exploration drilling will also continue to focus on expansion of the R zone, NXT zone and the High Grade Zone (HGZ) up-plunge and at depth.
The Red Lake gold mine in the town of Red Lake in the province’s northwest is the world’s richest gold mine and is mined at the rate of 450 tonnes per day with an average grade of over 45 grams per tonne (1.3 ounces per tonne).
MINING OPERATIONS IN RED LAKE MINE
Mining methods in the Red Lake mine is underground mining methods by gold mining process Overhand Cut and Fill (OCF), Underhand Cut and Fill (UFC), and Long Hole (LH) for maximum ore extraction at Red Lake gold mine. Gold mining process in Red Lake high-grade zone require specialized expertise operation, which primarily drilling and survey mineralisation of a narrow vein system.
Diamond drilling has been carried out at the Red Lake Gold Mines since the beginning of their operations. Over the years various lithological descriptions have been developed. The primary mining method at the Campbell Complex is longhole (65%) followed by conventional overhand cut and fill (30%) and approximately 5% development ore.
The longhole mining includes both longhole panel mining and longhole sill recovery. Sill recovery in mined out (shrinkage) areas is done from footwall access drifts to minimize worker exposure to highly stressed areas within the ore zone.
Longhole panel mining is performed on 50 foot sublevel intervals with typical widths of 8 to 20 feet and typical strike lengths from 50 to150 feet. Larger stopes may be mined transversely through the use of drawpoints on 50 foot intervals.
Mechanised cut and fill is used over conventional longhole where feasible, especially in areas where the dilution is high and orebodies are narrow or discontinuous.
Cut and fill headings are mined approximately nine feet high at widths ranging from 4 to 30+ feet depending on the ore zone. When longhole is the chosen method, stope spans are minimized, blast size is kept small, and pastefill is placed as soon as possible after each stope is mined out.
GOLD PROCESSING IN RED LAKE MINE
The processing plant in red lake mine operations consist of grinding, gravity concentrating, leaching, carbon-in-pulp (CIP), carbon elution and reactivation, electrowinning, bullion smelting/refining and cyanide destruction, flotation and concentrate handling—all of which are required to recover the gold in Red Lake’s ore types.
Crussing Mineral Ore In Red Lake Mine
A jaw and standard cone crusher operates in open circuit and a short head cone crusher operates in closed circuit with an 18-mm vibrating screen.
Fine ore is conveyed to the mill by inclined conveyor discharging, via a conveyor, to a 3,100-tonne fine ore bin.
Grinding is achieved in a two-stage rod/ball mill circuit. The ore from the fine ore bin is fed to the rod mill via two slot feeders and a conveyor.
The rod and ball mill is operated at 26.7 rpm, 67% of critical speed, and 22 rpm, 74% of critical, respectively. The rod mill is powered by 500 horsepower motor while the ball mill has a 1250 horsepower motor.
The grinding circuit consists of a 2.74-m x 3.8-m (9-ft x 12.5-ft) rod mill and 3.8-m x 4.7-m (12.5-ft x 15.5-ft) ball mill discharging, through trommel screens, into a common primary pump box. The slurry is pumped to a cyclo-pac with 8 units of 250-mm CVX10 cyclone.
The processing plant in red lake mine operations consist of grinding, gravity concentrating, leaching, carbon-in-pulp (CIP), carbon elution and reactivation, electrowinning, bullion smelting/refining and cyanide destruction, flotation and concentrate handling—all of which are required to recover the gold in Red Lake’s ore types.
Three types of gold occur in the Red Lake Mine and for mineral ore processing requiring various processing method.
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Gravity Concentrating Process In Red Lake Mine
Coarse gold is recovered from the ore via the gravity concentrating circuit. A portion of the ground slurry from the single 1200 H.P. ball mill is fed to two Knelson Concentrators which produce a gravity concentrate that is upgraded on a Diester Table to a concentration of approximately 75% gold, and directly smelted into bullion.
Process Carbon In Pulp In Red Lake Mine
Finer grain gold is dissolved in the cyanidation or leach circuit in which sodium cyanide is introduced to the process stream. The leach circuit consists of four tanks each overflowing from one to the next.
In the leach tanks the gold is dissolved from a solid state into solution. Gold is removed from solution and onto granular carbon particles in the C.I.P. (Carbon in Pulp) tanks. Values from the carbon are removed in the Carbon Strip Plant, in which a high grade gold bearing solution (loaded eluate) is generated.
Carbon is transferred from the CIP1 tank to the CIL tank to increase the carbon grade to approximately 9,000 g/t. Approximately 1.3 tonne per day of loaded carbon is removed every day in a single operation with a SALA vertical recessed impeller pump that discharges over a 20-mesh screen.
The carbon flows by gravity into a loaded carbon bin and undersize is returned to the CIL tank. Acid washing is performed using 5% by weight hydrochloric acid on every second batch of loaded carbon.
The loaded carbon is stripped using 40 bed volumes of 1% caustic solution and 0.1 % cyanide at 140oC and 480 kPa. Stripped carbon is educted from the strip vessel over a 16 mesh de-watering screen. The screen oversize (stripped carbon) flows into the kiln feed hopper for de-watering and undersize (fine carbon) into the eductor water tank.
The de-watered stripped carbon is then fed into a carbon regeneration kiln with zone 1 and 2 set at 450 and 650oC, respectively. The stripped solution is pumped to the electrowinning cell for gold plating. The barren solution is recycled to the strip solution tank.
This loaded eluate, or pregnant solution, reports to two electrowinning cells where, under an applied voltage and current density, gold precipitates out of solution and back into its solid state as “cathode sludge”. This sludge is also directly smelted into bullion for subsequent shipment to the refinery.
Flotation Circuit Process In Red Lake Mine
The cyclone overflow and underflow report to the flotation and ball mill, respectively. Two cyclones, one feeding each Knelson concentrator, are mounted on independent underflow boxes away from the cyclo-pac. These boxes are equipped with a concentrator feed inlet and an overflow return line to the primary pump box. The concentrator cyclones are fed from the cyclo-pac distribution manifold and the overflow returning to the cyclo-pac overflow launder
The cyclone overflow is gravitated to a 3-m2 Delkor screen and the undersize to a pump box that is then pumped to a 10-minute conditioner tank. The slurry reports to a 7-cell bank of Denver DR-500 rougher cells.
These cells are designed with double transverse froth overflow launders per cell and discharge into a single froth launder. Concentrate reports to a 4-cell bank of Denver DR-100 cleaner cells. Cleaner tails are recycled back to the DR-500 cells and the final concentrate assays approximately 15% sulphur and is pumped to a 9-m concentrate thickener.
The overflow from the concentrate thickener is recycled to the conditioner. The flotation tailing is transferred to a 27-m diameter thickener with the underflow sent to the flotation tails leaching circuit and the overflow to the process water tank. The reagents are stage added to the conditioner and junction box. A Courier 30XP on-stream analyzer is used to monitor and control the flotation performance.
Thickened flotation tailing (60% solids) is leached for 20 to 28 hours. The initial pH and cyanide concentration is maintained at 11.5 and 500 ppm, respectively. The total lime and cyanide consumption on both oxide and flotation tailing circuit is 2.1 and 0.75 kg/tonne.
The leached slurry, a combination of oxide and flotation tails, is pumped into a train of six CIP tanks; each has a slurry retention time of 50 minutes. Carbon retention is accomplished by the use of 2.25 m2 KEMIX wedge screens with a carbon retention time of approximately 10 days (carbon concentration 35 g/l). The 6 x 16 carbon advances 8 times over a 24-hour period counter-current to the pulp flow by a SALA vertical recessed impeller pump suspended in the pulp.
Refinery Process
The gravity concentrate and electrowinning sludge are melted simultaneously. The mixture of gravity concentrate and EW sludge is fluxed with nitrate, borax, silica, fluorspar and manganese dioxide. The charge is melted in a 4.5 cu ft Bradley induction furnace. The reagents combine with impurities to form a slag that is recycled. The gold is molten, purified and poured into 1,000 troy ounce bullion bars. The bullion averages 92% gold and 6% silver.
MINING OPERATIONS IN RED LAKE MINE
Mining methods in the Red Lake mine is underground mining methods by gold mining process Overhand Cut and Fill (OCF), Underhand Cut and Fill (UFC), and Long Hole (LH) for maximum ore extraction at Red Lake gold mine. Gold mining process in Red Lake high-grade zone require specialized expertise operation, which primarily drilling and survey mineralisation of a narrow vein system.
Diamond drilling has been carried out at the Red Lake Gold Mines since the beginning of their operations. Over the years various lithological descriptions have been developed. The primary mining method at the Campbell Complex is longhole (65%) followed by conventional overhand cut and fill (30%) and approximately 5% development ore.
The longhole mining includes both longhole panel mining and longhole sill recovery. Sill recovery in mined out (shrinkage) areas is done from footwall access drifts to minimize worker exposure to highly stressed areas within the ore zone.
Longhole panel mining is performed on 50 foot sublevel intervals with typical widths of 8 to 20 feet and typical strike lengths from 50 to150 feet. Larger stopes may be mined transversely through the use of drawpoints on 50 foot intervals.
Mechanised cut and fill is used over conventional longhole where feasible, especially in areas where the dilution is high and orebodies are narrow or discontinuous.
Cut and fill headings are mined approximately nine feet high at widths ranging from 4 to 30+ feet depending on the ore zone. When longhole is the chosen method, stope spans are minimized, blast size is kept small, and pastefill is placed as soon as possible after each stope is mined out.
GOLD PROCESSING IN RED LAKE MINE
The processing plant in red lake mine operations consist of grinding, gravity concentrating, leaching, carbon-in-pulp (CIP), carbon elution and reactivation, electrowinning, bullion smelting/refining and cyanide destruction, flotation and concentrate handling—all of which are required to recover the gold in Red Lake’s ore types.
Crussing Mineral Ore In Red Lake Mine
A jaw and standard cone crusher operates in open circuit and a short head cone crusher operates in closed circuit with an 18-mm vibrating screen.
Fine ore is conveyed to the mill by inclined conveyor discharging, via a conveyor, to a 3,100-tonne fine ore bin.
Grinding is achieved in a two-stage rod/ball mill circuit. The ore from the fine ore bin is fed to the rod mill via two slot feeders and a conveyor.
The rod and ball mill is operated at 26.7 rpm, 67% of critical speed, and 22 rpm, 74% of critical, respectively. The rod mill is powered by 500 horsepower motor while the ball mill has a 1250 horsepower motor.
The grinding circuit consists of a 2.74-m x 3.8-m (9-ft x 12.5-ft) rod mill and 3.8-m x 4.7-m (12.5-ft x 15.5-ft) ball mill discharging, through trommel screens, into a common primary pump box. The slurry is pumped to a cyclo-pac with 8 units of 250-mm CVX10 cyclone.
The processing plant in red lake mine operations consist of grinding, gravity concentrating, leaching, carbon-in-pulp (CIP), carbon elution and reactivation, electrowinning, bullion smelting/refining and cyanide destruction, flotation and concentrate handling—all of which are required to recover the gold in Red Lake’s ore types.
Three types of gold occur in the Red Lake Mine and for mineral ore processing requiring various processing method.
.
Gravity Concentrating Process In Red Lake Mine
Coarse gold is recovered from the ore via the gravity concentrating circuit. A portion of the ground slurry from the single 1200 H.P. ball mill is fed to two Knelson Concentrators which produce a gravity concentrate that is upgraded on a Diester Table to a concentration of approximately 75% gold, and directly smelted into bullion.
Process Carbon In Pulp In Red Lake Mine
Finer grain gold is dissolved in the cyanidation or leach circuit in which sodium cyanide is introduced to the process stream. The leach circuit consists of four tanks each overflowing from one to the next.
In the leach tanks the gold is dissolved from a solid state into solution. Gold is removed from solution and onto granular carbon particles in the C.I.P. (Carbon in Pulp) tanks. Values from the carbon are removed in the Carbon Strip Plant, in which a high grade gold bearing solution (loaded eluate) is generated.
Carbon is transferred from the CIP1 tank to the CIL tank to increase the carbon grade to approximately 9,000 g/t. Approximately 1.3 tonne per day of loaded carbon is removed every day in a single operation with a SALA vertical recessed impeller pump that discharges over a 20-mesh screen.
The carbon flows by gravity into a loaded carbon bin and undersize is returned to the CIL tank. Acid washing is performed using 5% by weight hydrochloric acid on every second batch of loaded carbon.
The loaded carbon is stripped using 40 bed volumes of 1% caustic solution and 0.1 % cyanide at 140oC and 480 kPa. Stripped carbon is educted from the strip vessel over a 16 mesh de-watering screen. The screen oversize (stripped carbon) flows into the kiln feed hopper for de-watering and undersize (fine carbon) into the eductor water tank.
The de-watered stripped carbon is then fed into a carbon regeneration kiln with zone 1 and 2 set at 450 and 650oC, respectively. The stripped solution is pumped to the electrowinning cell for gold plating. The barren solution is recycled to the strip solution tank.
This loaded eluate, or pregnant solution, reports to two electrowinning cells where, under an applied voltage and current density, gold precipitates out of solution and back into its solid state as “cathode sludge”. This sludge is also directly smelted into bullion for subsequent shipment to the refinery.
Flotation Circuit Process In Red Lake Mine
The cyclone overflow and underflow report to the flotation and ball mill, respectively. Two cyclones, one feeding each Knelson concentrator, are mounted on independent underflow boxes away from the cyclo-pac. These boxes are equipped with a concentrator feed inlet and an overflow return line to the primary pump box. The concentrator cyclones are fed from the cyclo-pac distribution manifold and the overflow returning to the cyclo-pac overflow launder
The cyclone overflow is gravitated to a 3-m2 Delkor screen and the undersize to a pump box that is then pumped to a 10-minute conditioner tank. The slurry reports to a 7-cell bank of Denver DR-500 rougher cells.
These cells are designed with double transverse froth overflow launders per cell and discharge into a single froth launder. Concentrate reports to a 4-cell bank of Denver DR-100 cleaner cells. Cleaner tails are recycled back to the DR-500 cells and the final concentrate assays approximately 15% sulphur and is pumped to a 9-m concentrate thickener.
The overflow from the concentrate thickener is recycled to the conditioner. The flotation tailing is transferred to a 27-m diameter thickener with the underflow sent to the flotation tails leaching circuit and the overflow to the process water tank. The reagents are stage added to the conditioner and junction box. A Courier 30XP on-stream analyzer is used to monitor and control the flotation performance.
Thickened flotation tailing (60% solids) is leached for 20 to 28 hours. The initial pH and cyanide concentration is maintained at 11.5 and 500 ppm, respectively. The total lime and cyanide consumption on both oxide and flotation tailing circuit is 2.1 and 0.75 kg/tonne.
The leached slurry, a combination of oxide and flotation tails, is pumped into a train of six CIP tanks; each has a slurry retention time of 50 minutes. Carbon retention is accomplished by the use of 2.25 m2 KEMIX wedge screens with a carbon retention time of approximately 10 days (carbon concentration 35 g/l). The 6 x 16 carbon advances 8 times over a 24-hour period counter-current to the pulp flow by a SALA vertical recessed impeller pump suspended in the pulp.
Refinery Process
The gravity concentrate and electrowinning sludge are melted simultaneously. The mixture of gravity concentrate and EW sludge is fluxed with nitrate, borax, silica, fluorspar and manganese dioxide. The charge is melted in a 4.5 cu ft Bradley induction furnace. The reagents combine with impurities to form a slag that is recycled. The gold is molten, purified and poured into 1,000 troy ounce bullion bars. The bullion averages 92% gold and 6% silver.
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