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Volcanogenic massive sulphide (VMS) deposits

VMS deposits are base +/- precious metal-rich mineral deposits hosted by submarine volcanic sequences. They are generally formed by the exhalation of hot, metal rich fluids into cold seawater surrounding volcanic vents on the seafloor. These deposits have strong connections with the modern day "black smoker" deposits formed at spreading ridges.

The deposits represent major sources of copper, zinc, lead, gold and silver in a high grade:low tonnage ratio. Gangue minerals exist in the form of quartz, chlorite, barite, gypsum and carbonate. VMS deposits are found in most parts of Canada, and are significant producers in British Columbia, Manitoba, Ontario, Quebec, New Brunswick and Newfoundland.

VMS deposits tend to be restricted to one or more volcanic horizons. In the case of the Noranda camp, these episodic events commonly used pre-existing vent structures, which led to vertical stacking of ore bodies in the volcanic sequence. VMS deposits tend to occur in clusters, as the volcanic system typically forms multiple vents along the seafloor.

The stockwork zone beneath VMS deposits forms the conduit through which metal-rich fluids rise and produces a zone of semi-massive stockwork mineralization. Hydrothermal alteration forms a pipe around the stockwork zone and typically grades from an inner chloritized zone to an outer sericitic zone. A mound structure (see diagram) typically forms as the hydrothermal fluids exhale and is slowed by the presence of eruption breccia at the vent. This allows the formation of chimney structures, which collapse and add to the amount of sulphide breccia, further slowing the exhalation of later fluids, giving fluids time to cool and mix with seawater and increasing sulphide precipitation into the mound.

VMS mineralization is the primary target on the Company's McFauld's Lake area projects.

Archean Mesothermal Lode Gold Deposits

Archean mesothermal lode gold deposits are typically characterized by gold-rich quartz vein systems with associated supracrustal belts in low- to medium-grade metamorphic terranes. Typical features of this deposit type include high gold/silver ratio, vertical continuity and well-developed carbonate alteration haloes.

This style of gold deposit occurs in two types, based on host lithology, namely volcanic-associated and sediment-associated. The Timmins camp belongs to the former group, and includes world class deposits such as the Hollinger (19 million ounces of gold produced), McIntyre (10 million ounces of gold produced) and Dome (15 million ounces of gold produced) mines.

These deposits are typically associated with major lithospheric structural features, such as faults or shears, within greenstone belts or along their margins. The faults, and associated splays, which control gold mineralization are typically part of a larger deformational zone that can reach kilometers in thickness and several hundred kilometers in strike. The Destor-Porcupine Fault Zone (DPFZ), which hosts most of the gold deposits in Timmins, is a good example of such a regional feature.

The structural setting of the deposits or vein systems themselves is essentially a small-scale representation of the larger deformation zone, with veins generally occurring in the central sections of discrete shear zones. Veins may extend for limited distances into the enclosing, less deformed, rocks. As well, veins may form in dilation zones created by folding.

Archean mesothermal lode gold deposits are a major source of gold production in Canada and account for close to 20% of the world's cumulative gold production.

The target-type for the Company's Bristol Township project in the Timmins West Camp is Archean mesothermal lode gold mineralization.  

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