Mt Garnet Regional Geology
The Mount Garnet tin deposits are hosted in granite-intruded sediments with associated contact metamorphism and metasomatism.

The mineralisation including cassiterite, magnetite and fluorite, is contained within tabular skarn lenses that formed within carbonate-rich sediments.

The Silurian Chillagoe Formation, characterised by limestone – marble, chert, basic volcanics and siliciclastics, lies along the western margin of the Hodgkinson Province. Limestones of this formation are favourable hosts for skarn-associated tin mineralisation at Mount Garnet.

Gillian Geology
The Gillian tin deposit occurs as skarn lenses developed in altered limestone beds of the Chillagoe Formation which has been intruded by granites. The lenses are tin-iron skarns consisting of massive magnetite and goethite with fine grained cassiterite, the most common tin bearing mineral.

The deposit strikes north-south and has the dimensions 850 m north-south, 880 m east-west and 250 m vertically. In the western part of the deposit, mineralisation occurs as a number of steeply ipping tabular lenses, while mineralisation in the eastern part occurs, primarily, as a single lens.

Pinnacles Geology
The Pinnacles tin deposit occurs as a series of irregular skarn lenses developed in altered limestone beds of the Chillagoe Formation which has been intruded by granites. The deposit is a tin-fluorine-iron skarn consisting of thinly banded magnetite-fluorite, known as wrigglite, with fine grained cassiterite, the most common tin bearing mineral.

The deposit strikes north-south and has the dimensions 700m north-south, 500m east-west and 250m vertically. In the western part of the deposit, mineralisation occurs as a number of steeply dipping tabular lenses, while mineralisation in the eastern part occurs, primarily, as a single lens, see below.

The flat lying skarn occurs close to the surface and dips towards the centre of the deposit where it is up to 25m thick.

Windermere and Deadman’s Gully Geology
The Windermere tin deposit occurs as an irregular skarns pods developed in altered limestone beds of the Chillagoe Formation which has been intruded by granites. The deposit is a tin-iron skarn consisting of massive magnetite with fine grained cassiterite, the most common tin bearing mineral.

The Windermere deposit consists of a series of several, more or less vertically dipping, skarn pods striking more or less north-south. The deposit is known over a strike length of two kilometres. Drilling of the deposit has revealed that the mineralisation exists as ‘pods’ of various sizes. The larger intercepts seem not to extend along strike or down dip. The deposit does not seem to contain a clear contact zone of skarn formation resulting in the ‘pods’ referred to above. This makes it difficult to define a clear target across the 2 km strike length. A theory that the granite contact is deep (<150 m) and that the mineralising fluids have permeated through the host rocks to form the skarn pods has not been proven to date.

The geology of the Deadman’s Gully deposit, which lies on the same trend as Windermere about 750 m to the south, is similar to that of Windermere. Deadman’s Gully is smaller, being known over a strike length of about 100 m. The local geology is depicted below.

Mining method will be by open cut with an average mining cost per tonne of A$24.25/t. Pit designs were based on Whittle optimisation shells generated using preliminary operating cost estimates. Mine development and operation is reflected as contractor mining. Ore will be transported to the Mt Garnet concentrator subject to final agreement with Snow Peak.

The essential elements of the process plant design include the following primary comminution and flotation stages:
- Multi-stage crushing
- Primary grinding using the existing SAG mill and ball mills with one additional ball mill added from existing grind circuit
- Reverse Silica flotation through a series of conventional flotation cells with rougher and cleaner cells with additional primary cells added

The combined high iron concentrate material containing tin will report to final filter where moisture is extracted prior to being pelletised and fed to the tin roasting circuit.

Tin fume at 68% Sn will be recovered through a gas handling system consisting of gas cooling, followed by a series of filters (Bag House) with continuous recovery of SnO2 as a solid prill for dispatch to smelters. Final gas cleaning and lime scrubbing will ensure release of clean air to the atmosphere.

Magnetite will be continuously recovered from the rotary kiln d ........