The 2nd example of gold ore heap leaching - Summitville gold
2020-08-28 09:36Introduction：The 2nd example of gold ore heap leaching - Summitville gold mine heap leaching plant in southern Coloradostate The Summitvillegold mine in southern Colorado, USA, is a large opencast mining and heap leaching gold extraction joint venture,
The 2nd example of gold ore heap leaching - Summitville gold mine heap leaching plant in southern Colorado state
The Summitville gold mine in southern Colorado, USA, is a large opencast mining and heap leaching gold extraction joint venture, has a history of more than 100 years. The ore contains 1.2 g / t of gold and 0.3 g / t of waste rock. The ore body is about 8 kilometers in succession. 2/3 of the ore are siliceous lump ore and 1/3 of clay powder ore.
Opencast siliceous lump and clay powder ore were transported to two coarse ore bunkers respectively. The block ore was broken by a large rotary crusher of 1260 mm × 2100 mm, the production capacity was 1200 t / h, and the ore discharge was screened by vibrating screen (30 mm sieve hole), Sieve products into 2100 mm cone crusher. Crushed minerals and-30 mm sieve products are combined to be sent to medium ore hopper, and a certain amount of lime is added before entering ore hopper. The clay silt is sent to another mine by a 75 mm vibrating sieve. Cement is added to the product of the sieve and water is sprayed through the pellet belt to the ore hopper and Pelletized . The products of the screen were crushed by the E-type crusher and fed into another 2100 mm cone crusher parallel to the block system. Crushed ore entered the ore bin. The production capacity of the medium crusher is 750t / h, and the total of the two units is 1500 t / h.
The crushed ore was transported to the dipping site by a large dump truck, which was built in a valley filling type, covering an area from 0.1 square km (25 acres) in 1986 to 0.43 square km (106 acres) in 1987. Impervious treatment involves leveling the ground, compacting it with a roller, compacting it with clay, then spreading fine sand, and then laying high strength polyethylene (3 mm thick) with a layer of artificial felt to prevent the ore from piercing the polyethylene board. This impermeable layer has a tight structure, no leakage and can bear weight. A 100 ton dump truck and bulldozer are used to build the pile, the height of the lump pile is unlimited, and the height of the aggregate pile is generally not more than 4.57 meters.
The dilute sodium cyanide solution is pumped from the dispensing chamber to the serpentine pipe laid on the top of the mine heap. The solution is sprayed out of the small gap in the pipe and permeated evenly to the bottom from the top of the mine heap. The solution is sent by pump to the gold extraction plant. Local rainfall is low and can be sprayed for 24 hours. Winter cold snow, only half a year production. The spray velocity of lump ore pile is 2.72 ml / (m2·s), and that of granulated ore reactor is 1.7 ml / (m2 ·s).
There are 5 activated carbon adsorption columns, pressurized heating device for desorption of gold carrying carbon, zinc powder replacement unit, gold smelting furnace and activated carbon regeneration kiln connected with pipe each other and controlled by various metering instruments. There is no smell in the plant and few production personnel. Carbon adsorption 5 column series, lean liquid added appropriate amount of sodium cyanide and lime to return to heap leaching ore. Gold loaded carbon was desorbed by caustic sodium cyanide solution under heating and pressure, then replaced with zinc powder, filtered to obtain gold slime and sent to gas smelting furnace for gold smelting. The desorption activated carbon was regenerated and returned to adsorption for reuse. The system has 120 employees, working for 6 months, 7 days a week, one shift per day, 11 hours per shift.
3 million tons of ore were treated in 1986 and 16 million tons of ore were treated in 1987. The annual output of gold is 4 tons. The heap leaching rate is 80 %~ 85% and the total recovery is 70% ~ 75%.
