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GOLD The geology of individual deposits can be very complex, with mineralization often found at the hinges of fold structures. In general terms, the fault zone that runs through the Timmins-Porcupine camp separates the district's metasedimentary rocks and mafic volcanics from intermediate, felsic and mafic volcanics to the north and south, with large areas of intrusives to the south and west that may have been involved in the mineralization emplacement. Some areas of ultramafic volcanics are also found within the fault zone. Thus, for instance, the area containing the Timmins West complex forms the contact zone between mafic metavolcanic rocks to the northwest and metasediments to the southeast. Dipping steeply, the contact contains folds and shear zones that are associated with gold mineralization. The area between the Timmins West and Thunder Creek also contains a number of ultramafic metamorphosed pyroxenite and porphyritic intrusions. The gold occurs here in steeply plunging mineralized zones that lie parallel to the local folding and structures, typically within 100 m of major shear zones. Lake Shore's exploration to date at Timmins West, Thunder Creek and Bell Creek has shown all of the mineralized shoots to be open at depth. Timmins West: The First into Production Lying 18 km west of the city, the Timmins deposit at the Timmins West mine was officially declared as being in commercial production at the beginning of 2011. Having established the project's viability with its 2007 prefeasibility study, in 2008 Lake Shore began the development of an access ramp as well as sinking the 710-m-deep production shaft. This was completed and equipped by mid-2010, with stoping beginning in the primary Ultramafic 1 zone. By the end of 2010, the mine was producing ore at an average rate of 1,600 mt/d. The mineralization here typically lies at the contact between mafic and sedimentary rocks, as well as within ultramafics. The utramafic-hosted ore begins at around 525 m below surface and, from deep drilling results achieved in 2011, the company believes the structure extends to at least 2,400 m depth here and at nearby Thunder Creek—the other key deposit at the Timmins West mine. The two deposits are now linked by 800-m-long haulages on both the 200 m and 650 m levels, with 30 E&MJ; • FEBRUARY 2013 Schematic of the orebodies and ramp development at the Timmins West complex. Thunder Creek having been declared in commercial production at the start of 2012, following the release of an initial resource estimate in November 2011. At the same time, Lake Shore merged the two deposits as its Timmins West complex, under common operational management. As Lake Shore's senior vice president for operations, Dan Gagnon, pointed out to E&MJ;, "the mine has a 10-year resource base at the moment, and a five-year reserve. To place that in context, the Dome mine has had a 10-year life for the past 100 years." While waiting for development to reach the Ultramafic ore zone, during 2009 Lake Shore began ore production from the Footwall and Main zones, which contain lower-grade, less continuous mineralization but which are closer to surface. From there, production progressed deeper, using longhole stoping on sub-levels 30 m apart, until the first Ultramafic stopes became ready during 2010. The mining focus then switched, with production from the more challenging upper levels being suspended once the higher-grade ore was available, with the first 20 m-high longhole stope measuring over 75 m long by up to 35 m wide. During 2012, the company focused on extending the existing spiral ramps at both Timmins West and Thunder Creek, with the aim of reaching a depth of around 800 m on each by the year-end. All of the ore produced is trucked by a local contractor about 42 km to the Bell Creek mill for processing and gold recovery. Bell Creek Mill: Key to Conserving Capex The availability of the Bell Creek mill and mine at a cost to Lake Shore of around C$10 million in cash, shares and warrants was instrumental in providing the company with a ready-made processing plant that could underpin development at Timmins West. With a conventional carbon-in-pulp circuit, the mill had been built by Canamax Resources when it operated Bell Creek between 1986 and 1991. Subsequent operators, Falconbridge Gold and Kinross Gold, ran the mine for a further three years before it was shut in 1994. Total output during the eight years it was in operation came to some 575,000 mt grading 5.6 g/mt, giving nearly 113,000 oz of gold, all of which was handled by the existing mill. After acquisition, Lake Shore refurbished the plant to a throughput of 800 mt/d, then increased this first to 1,500 mt/d in 2009, and to 2,000 mt/d by the start of 2012. At the time, the company pointed out that the refurbishment cost was significantly lower than the capex involved in building a whole new mill from the ground up. In addition, the quicker start-up enabled it to begin processing development ore and so generate some cashflow. Bell Creek is an Archaean-aged mesothermal gold deposit, hosted in a metavolcanic/metasedimentary fold/fault sequence that itself lies between two significant faults. The gold mineralization is typical of that found in the district, being found in www.e-mj.com