Suriname Gold Company (Surgold), a wholly-owned subsidiary of Newmont Mining Corporation, is developing the Merian gold mine approximately 66km south of Moengo and 30km north of the Nassau Mountains in Suriname.
Suriname’s Ministry of Natural Resources granted environmental approval for the gold project in December 2013. Construction started in August 2014 and commercial production is expected to begin in 2016. The Suriname Government has the option to acquire 25% equity in the gold project.
The Merian open-pit is expected to produce up to 400,000oz of gold per annum over its estimated mine life of 11 years. In addition, the project will create 2,500 jobs during the development phase and 1,300 jobs during operation.
Merian gold mine geology and reserves
Aurora Gold Project, Guyana, South America, Guyana
Aurora’s total gold production is estimated to be 3.29 million ounces over its 17-year mine life.
Merian gold mine is located within the Guiana Shield, which comprises of distinct, east-west trending belts of low-grade metamorphic rocks separated by large areas of granitic rocks and gneisses. The bedrock geology of the mine consists of inter-bedded graywackes, mudstones, siltstones, sandstones and minor volcaniclastics of the north-west trending and south-east plunging Armina Formation.
Gold mineralisation at Merian occurs within saprolite, saprock or un-oxidized rock. The saprolite zone, comprised of sedimentary rocks oxidised to a mixture of clays such as kaolinite and iron oxides, extends up to a depth of 100m below surface and above a transition zone comprised of partially-weathered rocks.
Merian open pit mine was estimated to contain 4.2 million ounces (Moz) of gold reserves as of December 2013.
Mining and processing of ore from the Merian gold mine
“Construction started in August 2014 and commercial production is expected to begin in 2016.”
Conventional truck and shovel operation along with drill and blast methods will be employed at the open-pit mine. The major mining fleet for the project will include Hitachi EX3600 hydraulic excavators, Caterpillar 785D haul trucks, blast hole drills, motor graders, CAT D10T dozers, and other ancillary equipment.
Fresh rock from the mine will be crushed at the mine site while the saprolitic rock will be directly screened before being transported to the processing plant. A blend of saprolite and fresh rock will be processed at the plant. The milling capacity of the plant will be eight million tonnes per annum (Mtpa).
The crushed ore will first pass through a grinding circuit comprising of a semi-autogenous (SAG) mill, a pebble-crusher and a ball mill. Fine ore particles will be delivered to a trash screen and thickened prior to leaching, whereas the coarser material will be re-circulated through the grinding circuit. Coarse gold will be recovered from the grinding circuit through a gravity concentrator and sent directly to the refinery.
Cyanide and lime will be mixed to the ore slurry for dissolving the gold into the solution. The slurry will then proceed from the leaching circuit to the carbon in pulp (CIP) where it will be mixed with activated carbon to adsorb gold. Slurry will then go to the tailings processing facility and the carbon will be delivered to the elution circuit where gold will be recovered using electrowinning process.
Tailings produced from the plant will be treated using a combination of tailings washing and thickening and an air/sulphur dioxide (air/SO2) cyanide detoxification system before disposal.
Construction and infrastructure
Major construction works include the development of borrow pits, construction of a process plant, a tailings storage facility, and a 700m long airstrip to be used for the export of gold and personnel transport during health and safety emergencies.
Power supply for the gold mine will be provided by a 62.3MW on-site heavy fuel oil (HFO) power plant. A small diesel power plant will also be used to supply power during the pre-production phase. It will also be used as a back-up during emergency in the operational phase.
