The Timmins Talc-Magnesite deposit is a hydrothermally altered ultramafic rock composed, at its core, largely of talc and magnesite although, at its fringes, the content of calcium in the carbonate increases.

The deposit under consideration has long been viewed as a potential source of magnesite and talc. These minerals are found in a variety of deposit types throughout the world and have a variety of end uses.

The best known of the minerals directly and widely exploited for its magnesia content is magnesite (MgCO3), one of the calcite group of rhombohedral carbonates, which includes calcite (CaCO3), siderite (Fe2CO3) and rhodocrosite (MnCO3), among others.

Although the genesis of natural magnesite deposits can be complex, it is distinguished in nature in two distinct physical forms, namely crystalline, (with a wide range of visible crystal sizes) and cryptocrystalline, sometimes referred to as amorphous, where the crystal size is not detectable to the eye and will range from 1 to 10 micrometers. The two types not only differ in crystal structure but in the sizes of the deposits and modes of formations.

Large-scale talc deposits form when magnesium in magnesium-rich rocks reacts with hydrothermal silica in the final phases of regional or contact metamorphism. Most commonly, talc (Mg3Si4O10(OH2)) or steatite (the massive and fine grained form of talc) replaces serpentine in an ultramafic rock like peridotite, either completely or m ........

The proposed mining method for the Timmins Talc-Magnesite project is open pit mining with truck haulage delivering to a process plant located approximately 1.5 km southwest of the deposit. The average life-of-mine waste to plant feed ratio is 1.28:1. Mining will be by drilling and blasting for the bedrock, with the overlying overburden not requiring blasting.

The deployment of a contractor fleet has been assumed to manage pit operations, run-of-mine stockpiling and crushing. The final bench height in the open pit was designed for 20 m, with operational benches advancing in 10-m lifts.

Contractor fleet will be deployed to manage pit operations and crushing. Unit mining rates were provided by a regional contractor reflecting a typical fleet of 5-yd3 excavators and wheel loaders, 50-t trucks, track dozers, water trucks, service trucks and portable crushing and grinding equipment. Drilling and blasting would also be contracted and articulated trucks would likely be rented to address the overburden stripping campaigns.

The process facilities have been designed to treat 500,000 t/y of talc-magnesite ore, mined at the Timmins Talc-Magnesite mine. The plant will operate continuously with 85% availability to exceed 310 days per year.

The production of talc and magnesium oxide will involve processing the ore through a series of crushing, grinding, flotation, leaching, evaporation, decomposition and sintering steps.

A contractor will be responsible for crushing, screening and stockpiling the ore. Reclaimed ore will be conveyed to a tertiary crusher, followed by a primary grinding mill to reduce the particle size. The ground ore will be treated in rougher and cleaner flotation circuits where talc will be recovered to the concentrate streams. Flotation tails will be pumped to separate leach circuits. Talc will be flash dried, micronized and stored in silos.

Magnesite and other minerals contained in the flotation tails will be dissolved in the leaching circuit. The impurities ........