New Jersey Mining Co. has commenced production from the Golden Chest mine and gold concentrate production from its New Jersey mill in Idaho. After completing the initial underground development (main haulage drift, secondary escapeway, and ventilation raise), Juniper Mining, operator of the Golden Chest mine, produced the first ore in November and began delivering ore to the New Jersey Mill in mid-December. Since that time, the mill has processed approximately3,500 tons of ore, steadily building toward design capacity of 400 tons per day. The first concentrate shipment will depart for the smelter in early February. As expected, gold recovery to concentrate has averaged about 94%.
Small Mine Development Corp., Juniper’s underground mining contractor, is using a modern rubber-tire fleet, cut-and-fill mining methods, and 14- x 14-ft development drifts at Golden Chest. The stopes mined thus far were at the very top of the Skookum Shoot. The ore processed at the mill in December and early January averaged 0.12 oz/ton of gold. While that is lower than the average grade of the Skookum Shoot Deposit, which is estimated at 0.32 oz/ton, much of that ore came as an addition to the original mine plan. Juniper expects to mine approximately 140,000 tons of ore grading 0.32 oz/ton over the next 16 months.
“We believe New Jersey Mining is unique among its peer group for the diversity of our talent and assets,” said Patrick Highsmith, New Jersey Mining’s president and CEO. “Our team has done a tremendous job preparing the mill for startup. Gold recovery has been excellent and all indications are that we are ready to run at full throttle in February.”
New Jersey Mining commissioned the upgraded mill in November and used the time prior to startup to complete operator training. The mill encompasses crushing, grinding, gravity, and floatation circuits, augmented by paste tailings disposal, concentrate leach, and filtration capabilities. The entire milling circuit is fully operational; and the gradual mill ramp-up has facilitated a number of hardware and system adjustments that will help ensure a smooth transition to full production.
The milling agreement between New Jersey Mining and Juniper provides for a three-month ramp-up period, during which both groups will accelerate production toward design capacity. Mine production is currently constrained by back-filling operations on the upper levels, but Juniper reports that it will accelerate considerably in February.