Kutcho copper-zinc project is being developed by Kutcho Copper (formerly Desert Star Resources), in the Liard mining division, northern British Columbia, Canada.
The high-grade copper-zinc project’s pre-feasibility study completed in July 2017 predicts annual production of 15,000 tonnes (t) of copper and more than 20,000t of zinc over 12 years of estimated mine life.
Kutcho Copper started resource expansion drilling campaign at the project site in June 2018 and expects to double the resource estimate of the property by mid-2019.
The feasibility study for the project is expected to be completed by the end of 2019 and the construction decision is anticipated in 2021.
Kutcho geology and mineralisation
Situated approximately 100km east of Dease Lake, the Kutcho property covers 17,060ha in the Liard mining division of northern British Columbia and lies within the eastern end of King Salmon allochthonous belt of permo-triassic island arc volcanic rocks.
The Kutcho project mainly comprises three identified Kuroko-type volcanogenic massive sulphide (VMS) deposits known as Main, Sumac and Esso.
Mineralisation in the Main deposit, which is the biggest among the three, is irregularly disseminated and dips at 45º to the north but varies from 38º in the east to 63º in the west.
The Esso mineralisation is of a higher grade than that of the main deposit and is positioned at a depth from 400m to 520m below surface occurring at the western or the down plunge end.
Copper (Cu), zinc (Zn), silver (Ag) and gold (Au) are the payable minerals found in the Kutcho property.
Kutcho mine reserves
Kutcho property was estimated to hold 10.44 million tonnes (Mt) of probable ore reserves grading 2.01% Cu, 3.19%Zn, 0.37g/t of Au and 34.6g/t of Ag, as of July 2017.
The measured and indicated resources of the project were estimated to be 16.85Mt grading 1.89% Cu, 2.87 % Zinc, 0.36g/t of Au and 32.8 g/t of Ag.
Mining method for Kutcho
Kutcho is proposed be an underground mining operation supplemented by pre-stripping of a small starter pit on the main deposit. The starter pit will provide the initial production of ore to gain full mill capacity, while the underground mine is expected to provide all mill feed for production from the second year of mining at Kutcho.
Mechanised cut and fill with paste backfill mining method will be employed to extract ore from shallow regions of the deposit, while sublevel long hole stoping method will be employed to target ore deposit in deeper regions.
Copper-zinc processing at Kutcho
Run-of-mine ore will go to the nearby 2,500 tonne per day (tpd) capacity processing facility for the production of copper and zinc concentrates with 84.7% copper recovery and 75.7% zinc recovery.
Kutcho ore will first pass through a grizzly feeder and be crushed into particles of size P80 125mm by a primary jaw crusher.
The crushed particles in the stockpile will be fed into a 750kW primary semi-autogenous grinding (SAG) mill followed by secondary grinding in a 1,300kW ball mill. The discharge from the SAG mill and the ball mill will undergo sequential floatation to produce copper and zinc concentrates.
The concentrates will be thickened and dewatered to a moisture content of 8%, before being transported to the Port of Stewart or to the railway loadout in Kitwanga, for export.
Tailings from the processing plant will go to a paste backfill plant for the production of a cemented paste which will be used as a backfill in the underground mine.
Infrastructure at Kutcho copper-zinc project
The project is accessible through a 100km-long seasonal road from Dease Lake and through an air strip located 10km away from the project.
Wells will be drilled on the mine site to enable continuous supply of fresh water. A water treatment plant will also be setup for supplying water to the processing plant.
The estimated power requirement for the project is 52GWh/year, which will be supplied by LNG power generators.
Metals purchase agreement for Kutcho
Kutcho Copper signed a $65m-worth early deposit precious metals purchase agreement (PMPA) with Wheaton Precious Metals in December 2017.
Wheaton Precious Metals will provide $100m support for the development of the project.
Contractors involved with Kutcho copper-zinc project
Ausenco Engineering is responsible for preparing the feasibility study of the project. JDS Energy & Mining (JDS) prepared the pre-feasibility study of the project.
Sim Geological provided resource modelling services, while Holland & Holland provided metallurgical engineering and process design services during the pre-feasibility study phase of the project.
Terrane Geoscience provided geotechnical engineering services, while SRK Consulting provided the open-pit and underground mine design.
ERM Consultants Canada and Rescan Tahltan Environmental Consultants were engaged for the environmental baseline studies and permitting.
Lorax Environmental provided hydrology and hydrogeological modelling. OnSite Engineering provided road design and engineering services.