Mar 10 2015
West Kirkland Mining Inc. today announces that the ongoing prefeasibility study for the Hasbrouck and Three Hills oxide, at surface gold deposits is proceeding as planned.
The project comprises 70.9 million tonnes (Mt) grading 0.56 grams per tonne (g/t) AuEq for 1.28 million gold equivalent ounces in the Measured and Indicated categories and 63.4 Mt grading 0.37 g/t AuEq for 0.76 million ounces in the Inferred category (Scott E. Wilson, Technical Report dated February 21, 2014 filed on www.sedar.com). West Kirkland holds a 75% interest in the Hasbrouck and Three Hills gold deposits and a large mineral rights position near Tonapah, Nevada.
HPGR Improves Gold Recovery to 72.6% on Larger Deposit
As part of the prefeasibility work, the use of high pressure grinding roll (HPGR) technology in test work was successful at increasing gold recovery by heap leach methods at the larger Hasbrouck deposit. Gold recoveries at Hasbrouck increased from 60% using conventional crushing to an estimated overall 72.6% with HPGR. Silver recoveries remain unchanged at 11%. The current Measured and Indicated resource for the Hasbrouck deposit contains 811,000 ounces of gold and 18,149 ounces of silver (63.2 million tonnes at 0.41 g/t Au and 8.91 g/t silver).
Run-of-Mine Recovery, 79% at the Initial Deposit
At the Three Hills deposit test work on run-of-mine material with no crushing predicts 79% gold recovery at production scale. The Three Hills deposit consists of 151,000 gold ounces (7.7 Mt at 0.62 g/t Au) within the current Measured and Indicated resource. The prefeasibility study and filed plan of operations with the Bureau of Land Management envisages an open pit heap leach operation, first at the Three Hills deposit and then at Hasbrouck.
Metallurgical Details
The results confirm that using HPGR for tertiary crushing at the Hasbrouck deposit will improve project economics. HPGR recoveries obtained in this test program and the capital required will be incorporated in the prefeasibility study to be published in early 2015.
HPGR is a proven technology used for several decades in many applications globally. Compared to the rock-on-steel breaking action of conventional crushing, HPGR's rock-on-rock breaking action produces finer particles with more micro-fractures, both effects tending to increase recovery. Additional benefits are expected to be lower specific energy and lower wear part consumption.
It is believed that the higher capital cost of HPGR technology will be more than offset by gains from increased recoveries and lower operating costs. The capital cost of an HPGR would be partially offset by saving the cost of the two cone crushers it would replace. Final estimates of the costs will be part of the prefeasibility study by independent engineers Mine Development Associates (MDA). Metallurgical testing on the HPGR and run of mine samples from the Three Hills deposit have been completed by Kappes Cassiday & Associates (KCA), an experienced firm from Reno.
Run-of-mine recoveries on the Three Hills deposit announced on December 3, 2014, were estimated from a 12 tonne bulk sample and leach program also performed by KCA.
Metallurgical recoveries were calculated by independent engineering firm H.C. Osborne and Associates which is part of the prefeasibility study team.
Both the Three Hills and Hasbrouck test results will inform the detailed flow sheets and design work for the prefeasibility study.
Permitting
West Kirkland started work on permitting the Three Hills mine immediately after acquisition. The Company submitted a plan of operations to the Bureau of Land Management on November 13, 2014, seven months after acquisition (see news release dated November 25, 2014). Independent consultants, MDA and Enviroscientists Inc. are working closely to ensure that plans utilized in the prefeasibility models are consistent with the submitted plan of operations. A significant portion of the design work submitted with the Three Hills plan of operations is at feasibility level.
All necessary baseline studies have been completed at Three Hills, including biology and cultural. No issues or concerns which might prevent or delay permitting or project advancement have been identified.
Geology and Resources and Mining Approach
As part of the prefeasibility study an updated resource model and a reserve plan will be completed taking into consideration current economic parameters and mine design. The deposits are at-surface within two prominent hills. Pits will be designed to minimize strip ratios and pre-stripping.
Exploration Potential
A review of the structural control of Three Hills has identified significant exploration potential to the east of the Three Hills deposit including an intercept of 39.6 meters of 1.36 g/t Au, from 54.9 meters to 94.5 meters in a hole originally targeted for monitoring ground water. The property position at Hasbrouck is large with excellent potential however corporate focus at this time in on engineering and mine design.
Corporate Focus
Since early 2013, the Company's strategy has been to acquire and develop one or more advanced stage gold properties in a good jurisdiction. To maintain focus on this strategy, West Kirkland announces the termination of its option agreement with Rubicon Minerals Corporation ("Rubicon") covering early stage exploration properties in northeastern Nevada. The Company retains its interest in the TUG property located in Utah. West Kirkland is now focused on advancing the Hasbrouck Project through engineering permitting and to a construction decision.
Source: http://www.wkmining.com/