Gunnison Copper Corp plans to mine up to 110 million tonnes a year of ore and waste to produce an average 75,000 tonnes per annum of copper via conventional openpit operations rather than use in-situ recovery (ISR) at 100%-owned Gunnison in Arizona, USA.
“The advancement of sulphide leaching technologies and the greater copper extraction of openpit mining and heap leaching has prompted GCC to focus on the openpit alternative to ISR,” the company said after releasing its latest preliminary economic assessment.
It said “optionality” on fully permitted ISR would be maintained.
A proposed US$1.3 billion, 18-year openpit and heap leach operation producing copper cathode via a circa-30 million tonnes per annum solvent extraction-electrowinning (SX-EW) process plant would be built on a current measured and indicated resource of 500 million tonnes grading an average 0.35% copper.
GCC has not yet done detailed economic studies on gravel and limestone “waste” products it estimates could be worth billions of dollars over the projected life of the proposed Gunnison mine.
The project is about 100km east of the city of Tucson in Arizona’s Cochise County.
GCC’s PEA, sans any assessment of the value of waste outputs, has put an after-tax net present value of $1.3 billion and internal rate of return (IRR) of 20.9% on Gunnison using an 8% discount rate and a long-term copper price of $4.10/lb.
The company says it has current operating permits for an ISR project “and there is a more streamlined amendment process to state and local permits to proceed with openpit mining”.
“The future of Gunnison has evolved to a lower risk openpit option with great economics,” said GCC senior vice president business development, Roland Goodgame.
“The opportunities the Gunnison project presents will benefit the local community and the greater Arizona economy.
“Significant direct jobs – over 650 – and indirect jobs will be created in addition to $842 million in revenues to local, state and federal tax.”
GCC, formerly Excelsior Mining Corp, expects to start producing copper at the smaller-scale, nearby Johnson Camp Mine next year.
