RE: OMI - Education22 Feb 2026 16:54
Based on reports surrounding Orosur Mining’s (OMI) Pepas prospect within the Anzá project in Colombia, a "flotation operation" refers to a potential, dedicated onsite processing facility needed to treat high-grade, complex mineralized material that is not suitable for standard third-party tolling.
What "Flotation" Means for Pepas:
Deposit Specificity: The Pepas ore is high-grade (approx. 5.46 g/t Au) and requires specific grinding (approx. 70 microns), which does not align with existing local third-party tolling facilities that operate at coarser grinds (approx. 120 microns).
Dedicated Infrastructure: To maximize recovery of the high-grade, near-surface gold, Orosur is evaluating constructing a dedicated, small-scale onsite plant rather than relying on external tolling.
Process: The operation would involve crushing and grinding the ore to a fine powder (70 microns), followed by froth flotation to separate the gold-bearing sulphide minerals from the waste rock.
ScienceDirect.com
ScienceDirect.com
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Cost of Flotation Operation vs. Tolling:
Construction Costs (Flotation Plant): Building a dedicated processing plant at Pepas is estimated to cost between US$70 million and US$100 million.
Operating Costs (Flotation): While building a plant is capital-intensive, the resulting high-grade operation aims to keep All-in Sustaining Costs (AISC) below US$1,150/oz.
Tolling Costs: While initially faster to implement, third-party tolling is likely unworkable for Pepas due to metallurgical incompatibility (fine grind required).
Economics: The high grade (5.46 g/t Au) and low stripping ratio of the deposit are expected to generate high margins that can support the high initial capital expenditure of a dedicated plant.
In summary, for Pepas, a dedicated flotation plant is a high-cap-ex ($70m-$100m) option designed to handle specific metallurgy and secure high-margin production, whereas external tolling, while having lower initial capital cost, is considered technically unsuitable.