Resource World Magazine

MINI NG Sandspring Resources advancing Toroparu in Guyana by Jennifer S. Getsinger, PhD, PGeo I n Precambrian days South America and Africa were nestled together and no ocean separated them. Gold formed in basaltic volcanic belts within granitoid masses that floated up to become future continents. Continued deformation and metamorphism during collision of continental masses concentrated gold in shear zones in what became greenstone belts. Eons later, humans found numerous gold-bearing deposits on the African side of this rich area, but on the South American side of the Atlantic Ocean the same rock mass was left largely unexplored. Tropical weathering had softened the hard rocks to saprolite and rainforests concealed the geological treasures. Although Sandspring Resources Ltd. [SSP-TSXV] began in Calgary in 2006, its core team had been working together since the 1980s and exploring its primary property, Toroparu, Guyana, since 1999. Back in the 1980s, Colorado geologists John Adams and others began to think about the potential for gold mines in the Guiana craton of northeast South America. Rich Munson began working with the group around the same time, and was instrumental in acquiring the Toroparu deposit for a company called ETK in 1999, later taken over by Sandspring, where he has served as CEO and director for several years. This article is, in part, based on a conference call with Rich Munson in Sandspring's head office in Centennial, Colorado, and with L. Werner Claessens from Sandspring field operations office in Georgetown, Guyana. Claessens discovered three gold deposits, now producing gold mines, in Africa. He says that the advantage of South America, especially Guyana, is that it is less explored, and so has a greater potential for discovery. Whereas in West Africa there are dozens of well-known and large gold mines in the Paleoproterozoic shield, in 36 www.resourceworld.com the Guiana shield in Guyana there are only three significant gold deposits (over 1 million ounces gold) currently under scrutiny, and none are yet in production. One of them is Sandspring's Toroparu gold-copper project in the positive pre-feasibility study stage, with 10 million ounces gold. In the western Guiana Shield in Venezuela, large gold-copper deposits have been found during a longer exploration history, including Choco, Las Cristinas, Las Brisas, and El Dorado. In Guyana, Sandspring Resources holds the Upper Puruni concession consisting of more than 1,000 km2 of property in a major northwesterly trending regional shear zone associated with intermediate plutonic rocks related to gold mineralization along contact zones with meta-volcanic rocks. Multiple phases of fracturing, phyllic–propylitic alteration, and quartz-carbonate veining have resulted in various zones of gold and copper mineralization. Mineral resources estimates reported on March 31, 2013, for the Toroparu deposit planned resource pit shell, with a cutoff grade of 0.30 g/t gold, include, for all rock types and in all deposits, combined measured and indicated resources of 240,240,000 tonnes grading 0.89 g/t gold for 6,894,000 ounces of gold and 0.084% copper for 444 million lbs of copper, with inferred resources of 129,525,000 tonnes grading 0.74 g/t gold for 3,090,000 ounces of gold and 0.042% copper for 120 million lbs of copper. The pre-feasibility study has enabled calculation of encouraging capital costs and a schedule involving various graduated stages of mining development, construction, and production, with mining starting in 2015. The idea is to mine the saprolite for gold first, as the highly weathered material is already sitting on top of the hard rock lode resource which bears gold and copper mineralization. Reverse circulation drilling at Toroparu in Guyana, South America. Photo courtesy Sandspring Resources Ltd. Saprolite mining can be achieved using a cyanide leach plant. As saprolite gold mining proceeds, it provides part of the capitalization necessary for building the facilities for mining the underlying fresh rock ore containing both copper and gold, and it removes overburden in the process. In a few years, all ore types will be able to be mined and processed with increasing capacity. Expected mine life is approximately 16 years. To summarize a table of reserve estimates of March 31, 2013, considering all ore types (saprolite gold as well as fresh bedrock gold and gold-copper ore), combined proven and probable reserves are 127,111,000 tonnes grading 1.00 g/t gold, with 4,107,000 ounces of gold, and 0.11% copper with 211 million lbs of copper, converted as 1.13 g/t gold equivalent or 4,634,000 ounces of gold equivalent. In 2012 Sandspring obtained an "environmental authorization" after a several-year process, and has recently entered into a cooperative agreement to construct a hydroelectric power plant. Due to the uninhabited location of the Toroparu property, there are no community issues, according to Rich Munson. n JUNE 2013

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