|
|
|
| Feasibility and Development Projects |
|
|
|
|
Escondida -
El Victor Underground |
|
|
|
|
|
|
|
|
|
|
Mulatos Mine - Infrastructure
Ore Processing
The Mulatos Processing Plant currently consists of a conventional crushing plant with a capacity of 14,000 tonnes per day, a conveyor that can handle up to 20,000 tonnes per day, a heap leaching facility, a carbon-incolumn circuit, and an electrowinning and refining plant.
Crushing takes place in three stages: Ore is first crushed to 80% passing a 15-centimetre screen in a primary jaw crusher. Ore from the primary crusher is then conveyed to a coarse ore stockpile with a storage capacity of 10,000 tonnes. Two apron feeders take the ore from the stockpile to feed the secondary crusher via conveyor. Secondary throughput reports to two tertiary crushers that crush to 3/8 of an inch. Alamos is currently "closing the crushing circuit" so that over-sized material will be recirculated through the crushing process so that only material that passes through the 3/8 of an inch screen will be delivered to the pad. The closing of the crusher is expected to compelted in late Q4-2009.
After crushing, the ore reports to the leach pad via a 1,600-metre conveyor, where ore is stacked and leached. The heaps are underlain by an impermeable plastic layer on top of 0.4 metres of compacted clay. To extract the gold from the ore, a low-concentration cyanide solution is applied to the ore on the leach pad using a low-pressure irrigation sprinkler system. Alamos installs inter-lift liners on the pad on a periodic basis. The use of inter-lift liners reduces the percolation time and thus reduces the time it takes to extract and produce gold from each lift in the heap.
The resulting gold-bearing solution percolates through the heap, is channeled to the pregnant solution pond, and is then pumped to the carbon-in-column circuit, where gold is recovered from solution. The barren solution is then recirculated to the heaps with added cyanide. Dore bars are produced on site and transferred to a third-party refinery for final recovery of gold and minor amounts of silver.
Power & Water Supply
The power plant currently consists of four 1,000 kilowatt and two 2,000 kilowatt generators.
Water for the operation is pumped from the Mulatos River at 950 meters above sea level. In addition to the river water, the Company has constructed a dam south of the waste dump that can impound up to 309,000 cubic metres of water and is less expensive to draw from than the river source because of its higher elevation of 1,270 metres.
|