There is no known formal industrial mineral ore deposit model for alunite. The characteristics for a model and some exploration criteria are derived from three publications: Hall (1978), Hall and Bauer (1983), and Hofstra (1984).

The local alunite deposit has been described, in the above-mentioned publications, as hydrothermal alteration of calc-alkaline volcanic rocks.

Alunite mineralization is found on four ridges that occur within the Blawn Mountain Project. Acid sulfate alteration associated with a shallow, possibly laccolithic intrusion altered the silicic-alkalic rhyolite porphyries, flows and tuffs belonging to the Miocene Blawn Formation and the Oligocene Needles Range Group. Alteration tends to be in linear bodies reflecting the role of normal faults in controlling the mineralization. Alteration is zoned away from the point of hydrothermal fluid upwelling. The mineralized ridges are erosional remnants of a once larger altered area.

Krahulec (2007) described the appearance of rocks from the silica cap and quartz-alunite zone as follows, “The Silica Cap is a zone of intense silicification believed to be the near-surface manifestation of the hydrothermal channel-ways. The silica is typically buff, dense, and massive but may be quite porous and vuggy locally and resemble a siliceous sinter… On the surface the Quartz-Alunite alteration zones are composed of white to cream to buff to gray to pink, generally fine grained, punky to dense, ........

Mining operations will use a conventional open-pit, truck and shovel mining approach. This is a typical and standard approach for many surface mining applications and takes advantage of the flexibility of the mining equipment. For Blawn Mountain, Area 1 and Area 2 will be developed in phases that will allow for optimizing the ore grades encountered in the deposit, while providing flexibility to the operation.

The mining plan for the PFS uses a nominal 3.75% K2O ore grade cut-off for Area 1 and a 3.50% K2O cut-off for Area 2. These cut-off grades were utilized in the development of the pit shells and mining areas for Area 1 and 2. In addition, two low-grade ore stockpiles will be developed, one for Area 1 and Area 2 respectively. Ore that is less than 2.75% K2O is considered waste material and will be placed in the waste dumps. The Area 1 low-grade stockpile will contain ore ranging in grade from 2.75% K2O to 3.75% K2O and the ore in the Area 2 low-grade stockpile will range from 2.75% K2O to 3.50% K2O. This low-grade ore will be fed to the processing plant after mine operations have concluded in year 28.

The mining production schedule is driven by the capacity of the processing plant. The ROM ore production schedule for direct plant feed is approximately 3.4Mtpy.

Primary Crushing
The ROM ore at minus 12in is delivered to the 400t dual loading hopper that feeds two parallel primary roll crushers, one operational and one stand by. Each roll crusher with a capacity of 425tph will crush the ROM ore to minus 3in.

The crushers are sized to operate 7,920 hours/year. The crushed ore will be conveyed to a collection bin which will feed two parallel screening/secondary crushing units.

Secondary Crushing
The collection bin will feed two dry crushing screens. Screen oversize will report to two secondary cage mills. The crushed product from the cage mills will be recycled back to the dry screens via bucket elevators. Screen undersize (P80 – 1mm) will be conveyed to the calciner feed bin. A dust collection system will be installed to manage the dust generated from dry crushing.

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