CEO George Salamis said this week the company had a better handle on ore types and possible optimum processing options after extensive exploration, and met-work.
"While expanding the already sizeable gold-silver resource at DeLamar via the drill bit is a large value-driver, demonstrating a clear direction for efficient low-cost gold and silver extraction, the metallurgy, is equally as important," Salamis said.
"These latest metallurgical results and stringent definitions of oxidation states, while preliminary, are exceptional. A high level of development and production optionality, including a number of lower-cost processing options, remains one of the distinct hallmarks of the DeLamar project and one of the primary reasons for acquiring the project."
The ongoing test programme has delineated about 24% of the combined projects' inferred resource as fully oxidised, 29% is transitional mineralisation and 47% is unoxidised.
DeLamar and Florida Mountain have combined inferred resources of 108.5Mt grading 0.71g/t gold-equivalent for 3.54Moz (split 2.27Moz gold and 108.5Moz silver).
The company said six bottle-roll tests on Florida Mountain oxidised material had given recoveries of 83.3% gold and 39.7% silver. Less than halfway through a 63-day preliminary column leach test on the same oxide sample returned recoveries of 72.4% gold and 23.4% silver.
The company believes the column testwork indicates the potential for successful heap leaching at Florida Mountain.
Further, the company has reconciled 10 years of historic monthly production from the 1980s and 1990s, which showed only a small decrease in mill recoveries when processing mixed ores. The company says this bodes well for future processing, with options to be outlined in an upcoming PEA due out in the second half of the year.
Integra added some of the deeper unoxidised mineralistion from DeLamar might be less amenable to direct cyanidation treatment and would require alternative processing such as flotation. Historical test-work on unoxidised material has demonstrated good recoveries in sulphide concentration, fine grinding and cyanidation.
The company is considering its future processing options for the PEA, including heap leaching with Merrill-Crowe; gravity concentration; agitated leaching with Merrill-Crowe; standard crush/grind/flotation with concentrate regrind/leaching; and standard crush/grind/floatation for concentrate product and possible tailings leaching.
"In these recent studies the breakdown of mineraliation types, the recovery rates, and the lack of high variability amongst the various mineralisation-types have surpassed our expectations. We are pleased with the progress and de-risking elements that the metallurgical studies have provided thus far and look forward to a full range of processing options to be outlined in the PEA," VP for project development Tim Arnold said.
Integra shares (TSXV:ITR) were trading at C76c Monday, 6% lower since the start of the year, capitalising the company at $58.8 million.
