Officials said that the pilot testing by Hazen Research confirmed the removal of arsenic to produce a clean cobalt concentrate from ICP's ore concentrates with rotary kiln roasting.
The testing with this method was previously demonstrated at a bench scale in late June.
eCobalt said that the newest studies returned a continuous run of 70 hours, including startup and shutdown, and concentrate was fed to it constantly for 50 hours with all factors of the process maintained as designed, including temperatures, pressures and flow rates.
"The study verified both the concentrate roasting process to produce a clean concentrate and the exhaust gas management system, which safely captured and removed arsenic and sulphur from the exhaust gas stream, as designed for vitrification and neutralisation, respectively," the company said.
With the positive result, it can now finish its optimised feasibility study later this year. It also continues to advance talks with cobalt traders on potential take-off deals or marketing efforts, and is still planning an updated resource model report next February.
ICP, located in the Idaho Cobalt Belt near Salmon, remains the sole near-term environmentally permitted primary cobalt deposit in the US, according to the company.
A 2017 feasibility study outlined target production rate of 800 US tons (726 tonnes) per day and a weighted average annual production of 2.4 million pounds/1.1 million kilograms of cobalt, 3.3 million lbs of copper and 3,000oz of gold over a mine life of 12.5 years.