The following is extracted from an NI-43-101 Prefeasibility Report titled “Bovill Project: Pre-Feasibility Study” completed by MillCreek Mining Group date March 31, 2020 a complete copy of which is available on the homepage of the website.
The Bovill Project is located near the town of Bovill in Latah County in northern Idaho. The project is located approximately 30 miles east-northeast of Moscow, Idaho and approximately 72 miles southeast of Spokane, Washington. Mineral tenure is held through 11 mineral leases, all of which are on State of Idaho endowment lands.
GEOLOGY AND MINERALIZATION
The region surrounding the Bovill Project is dominated by late Precambrian (Mesoproterozoic) metasedimentary rocks of the Belt Supergroup (Belt) and a major intrusive, the Thatuna granodiorite. Saprolitization of exposed intrusive rocks resulted from intense weathering in a humid, warm to hot climate during the Miocene epoch. In response to the strong weathering, much of the plagioclase feldspar and at least some of the mica in the near-surface portions of the Thatuna intrusives were altered to one or more varieties of clay minerals. The depth limit of weathering may initially have been fairly uniform; however, subsequent erosion has left a variable weathering profile with thickness roughly dependent on topography. At present, the depth of weathering may exceed 100 ft along ridges and be less than 3 ft in some valleys. The residual deposits consist primarily of kaolinite and halloysite clay intermixed with grains of potassium feldspar and quartz. Minerals of economic interest include: halloysite, an aluminosilicate clay mineral with hollow tubular morphology; and kaolinite, a hydrated aluminum silicate clay mineral, when calcined becomes a metakaolin clay, or dehydroxylated kaolin clay.
Seven drilling campaigns have been completed on the Bovill Project since 2000. Three types of samples have been collected from the Bovill Project to characterize the clay deposits: 1.) drill core samples to support resource estimation; 2.) channel samples for metallurgical characterization; and 3.) bulk samples for metallurgical test work.
The deposit at the Bovill Project has been found to be amenable to economic extraction using surface mining methods, with a standard ‘truck-shovel’ approach, and with little or no need for drilling and blasting. It is proposed that a contractor be used for mining operations. The mine plan has been developed to produce approximately 11 ktpa of halloysite and 23 ktpa of kaolinite, from an average of 233 kt of total ore and waste are mined each year, during’steady state’ production after project ramp-up. The ramp-up in production is based on percentages of the maximum throughput which starts at 27.5% in year 1, then 55% in year 2 followed by 81.5% in year 3 and full production in year 4 and beyond. Total ore throughput at the plant was designed to be at 130,000 tons per year.
The main products that I-Minerals intends to produce through this facility are metakaolin, standard and high-purity grade halloysite and a specialty sand product. A reasonable design has been proposed for the processing plant administration facilities, dry stack tailings system, and all required infrastructures including power, gas, and water supplies. The process design comprises five main areas: run-of-mine (ROM) stockpiling and crushing, clay / sand separation through the use of hydrocyclone classifiers; kaolin and halloysite clay separation by centrifuge; kaolin calcination and milling to produce metakaolin; halloysite upgrading; and product preparation.
An’optimized pit shell’ approach was followed in order to develop a pit shell development strategy that optimizes cash flow, and accounts for the various economic sensitivities of the project. Optimized pit shells were designed accounting for bench design, ramps, dilution, etc.
Halloysite grades average 8.3% and kaolinite grades average 17.7% through the life of mine.
ECONOMIC SUMMARY CAPITAL AND OPERATING COSTS
Initial capital costs, including a 15% contingency, are summarized in the table below:
Sustaining capital for the remainder of the LOM is estimated at $5.9M, or approximately $205,000 per year. The following tables summarize the mining costs including both contractor and owner mining costs. The total LOM costs were estimated to be $244M or $38.66 per ton (including both waste and ore) mined. This amount excludes $3.5M of capitalized contractor and owner pre-production costs.
DISCOUNTED CASH FLOW (DCF) ANALYSIS