The Marlin mine is 100% owned by Montana Explorada de Guatemala, S.A., a wholly-owned subsidiary of Goldcorp. The Marlin Mine is a conventional milling operation with a combination of open pit and underground mining which began commercial production in December 2005.
Marlin mine is in the western highlands of Guatemala, 48 kilometers southwest of the city of Huehuetenango, approximately 300 kilometers northwest of Guatemala City. The project lies within a highly prospective land package of approximately 100,000 hectares that encompasses the main Marlin deposit and other important mineralized zones. The Marlin mine has both conventional open pit mining and underground mining operations.
The Marlin deposit was discovered in western Guatemala through regional grass-roots exploration in 1998 by Montana Exploradora, S.A. and was later purchased by Francisco Gold Corporation in 2000. In 2002 Francisco Gold Corporation merged into Glamis and effectively transferred control of the Marlin mine to Glamis. Construction of the project commenced in early 2004 after the Guatemalan government issued the necessary environmental permits and licenses.
The Marlin mine is 25 kilometres by air west-southwest of the town of Huchuetenango or 300 kilometres by paved and gravel roads from Guatemala City. Goldcorp has completed substantial improvements on the roads leading into and within the project area.
Geology and Mineralization
The Marlin district is located 15-20 kilometres south of the Cuilco-Chixoy-Polichic Fault, a major sinistal transform fault that separates the North American and Central American cratons. Tertiary movement is documented to be over 150 kilometres. The Marlin deposit is on a projection of a southern splay off of the Plochic fault system. The northern side of the Polochic fault system contains Mesozoic sediments. The south side of the Polochic fault contains Paleozoic schist, gneiss and granite and a series of Tertiary mafic volcanic eruptive events composed mostly of dacitic to andesitic tuff, lahar and andesitic to basaltic flows. The Marlin deposit is located within the Tertiary mafic eruptive unit. The deposit trends in the same direction as the Polochic fault system.
There are four major lithologic units present at the Marlin site: pyroclastic deposits, marlin andesites, tertiary volcaniclastic sequence and porphyric dykes.
Mining & Operations
Conventional open pit mining methods using loader/truck operations are employed at the open pit. During 2008, a total of 1,697,137 tonnes of ore was mined at an average grade of 2.57 g/t gold and 40.5 g/t silver.
The underground operations use mechanized cut and fill and long hole stopping mining methods with underground loading equipment feeding haul trucks which transport the ore to the surface via ramp access. During the reporting period a total of 554,346 tonnes of ore was mined with an average grade of 9.7 g/t gold and 218.2 g/t silver.
The mill is designed to treat a minimal 1.82 million tonnes per year of ore. Ore is fed through a crusher prior to being introduced into the grinding circuit. Milling is conducted in a semi-autogenous grinding mill/ball mill circuit. The pulp produced by the milling is subjected to tank leaching with cyanide. After leaching the ore in the large tanks, the pulp is 'washed' in a series of settling units (counter-current decantation). This effectively produces two products: a clear gold and silver bearing solution and also a pulp without precious metal values. The gold and silver solution is sent to the refinery where the metals are precipitated out of solution through the addition of zinc. The precipitate is filtered and smelted to produce dore bars.