Excellent metal recovery lays foundation for production
Rockfire Resources plc (LON: ROCK), the gold, base metal and critical mineral exploration company, is pleased to announce that preliminary metallurgical tests from its 100%-owned Molaoi zinc deposit in Greece have returned excellent recoveries and concentrate grades for zinc, silver, lead and germanium. Copper and gold have also reported to the concentrates, adding high potential value to the future economics of the project. The metallurgical recoveries and grades attained in this round of tests significantly reduce process recovery and marketing risk.
Rockfire operates in Greece under its 100%-owned Greek subsidiary, Hellenic Minerals IKE. The on-going metallurgical test work is being supervised by Rockfire’s metallurgical consultants, BHM Process Consultants Pty. Ltd. (“BHM”) in Perth, Western Australia, using core drilled by the Greek Government.
· Excellent recoveries of zinc (89%) and lead (74%) have been achieved at Molaoi.
· Commercially saleable grades of zinc (57% Zn), silver (856 g/t Ag), lead (63.6% Pb), germanium (117 g/t Ge), copper (2.62% Cu) and gold (0.52 g/t Au) are readily achieved at Molaoi.
Zinc/germanium (Concentrate 1)
· First-pass metallurgical recovery of zinc is 89%, with this figure likely to increase with more detailed tests.
· The performance of the zinc system is reported by BHM as “excellent”, with a product grade of 57% Zn concentrate achieved in a single pass through a 3-stage flotation circuit. This is well above the desired product grade of 50% Zn contained for a saleable concentrate.
· Germanium reports to the zinc concentrate with a commercially competitive grade of 117 g/t Ge and is expected to be recovered as part of the zinc concentrate. This is expected to be a valuable credit in the concentrate.
Lead/silver/copper/gold (Concentrate 2)
· First-pass metallurgical recovery of lead is 74%, with this figure also expected to increase with more detailed test work.
· The lead circuit recovery is at a greatly over-concentrated value of 63.6% Pb concentrate achieved in a single pass through a 3-stage circuit configuration. This also far exceeds the market requirement of 40% – 50% Pb contained for a saleable concentrate.
· Silver recovery is 85.6% from the rougher tails, with 15.2% of the silver reporting through to the lead concentrate at a grade of 856 g/t Ag.
· Copper and gold both reported to the lead concentrate with grades of 2.62% Cu and 0.52 g/t Au. Historical copper mines exist in the northern part of the Molaoi tenement, suggesting copper and gold is likely to add material value to future concentrates.
· BHM expects that these recovery figures may be conservative, as there is much metallurgical development and many optimisation tests still to occur on the project.
· A differential flotation system was tested, by which the first stage targets the recovery of lead, copper and silver together into a single bulk sulphide concentrate, whilst sphalerite (zinc) is depressed. The second system targets the recovery of zinc (with germanium).
· The results available so far are for tests on composite samples from Molaoi core which have been blended to produce an “industry average” grade. The composite average feed grade used in the tests is 5.9% Zn and 1.6% Pb.
· Test work remains in progress on a much higher average grade composite sample of 18.9% Zn and 4.5% Pb, which Rockfire management believes may be closer to the ultimate feed head grade, based on drilling at Molaoi.
· More definitive testing will be initiated using core obtained from the planned diamond drilling later in the year. This work will include crushing, milling and abrasion work indices.
David Price, Chief Executive Officer of Rockfire, commented :
“We are extremely pleased with these initial metallurgical results, with saleable grades of zinc, silver, lead and germanium all being achieved at Molaoi. The inclusion of copper and gold reporting to the lead concentrate is a very important and pleasing development in our growing understanding of the deposit and is likely to add material value to future concentrates.
“The recovery of 89% of the zinc, 85.6% of the silver (in the rougher tails) and 74% of the lead bodes very well for the processing expectations for the project. This is an outstanding outcome from a single pass and significantly de-risks the expected metallurgical and marketing aspects of the project going forward.
“Future tests will include a locked (closed) cycle and optimisation of the conditions used for the concentration process. Rockfire’s metallurgical consultants expect the recoveries of each metal to further improve with more test work, which is planned. As part of this test work, crushing, grinding and abrasion work indices will be determined to assist in the design of the processing plant.
“The very high concentrate grades are particularly pleasing. The Molaoi tests, showing grades of 57% Zn, 856 g/t Ag, 63.3% Pb, 117 g/t Ge, 2.62% Cu and 0.52 g/t Au, are outstanding and prove that Molaoi is an exceptional deposit capable of producing a commercially saleable concentrate.
“We will continue to update the market with progress on our exploration across the Company’s portfolio of quality projects.”
For further information on the Company, please visit www.rockfireresources.com or contact the following:
Rockfire Resources plc:
David Price, Chief Executive Officer
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