Canadian Mining Journal


GOLD: Heap leach contemplated for Marathon and Leprechaun deposits

NEWFOUNDLAND – Marathon Gold Corp. of Toronto says that core samples from the lower grade portions of the Leprechaun and Marathon gold deposits are amenable to heap leaching. The two deposits contain 92% of the known resources in the Valentine Lake property, 55 km south of Buchans.

In addition to conventional pre-concentration and gold leaching processing technologies under development for the high grade zones, Marathon Gold is developing an integrated processing strategy that may include heap leaching of lower grade ores.

Thibault & Associates conducted short column leach tests of the material from the deposits. The Marathon sample contained 1.83 g/t Au and after 130 days, an extraction rate of 66.0% was achieved. The Leprechaun sample grading 1.66 g/t Au had a recovery rate of 72.7%. The majority of the gold was extracted within a 50-day period, and the rate slowed notably after 100 days.

Phillip C. Walford, president and CEO of Marathon said, “We will have to carefully study the trade-offs of higher cost, higher recovery conventional milling and high gold extraction versus the much lower capital costs and operating costs of a heap leach operation at lower gold recoveries. It is very important for the project economics to have these options available to us as we move to a PEA.”

More information, including technical reports, about the Valentine Lake project is posted at

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