The Rosh Pinah deposit is hosted by the Rosh Pinah Formation (Hilda Subgroup of the Port Nolloth Group), forming part of the Neoproterozoic Gariep Terrane deposited onto a Palaeo-Mesoproterozoic basement of granite gneisses and supracrustals. The Gariep Terrane is divided into two distinct tectono-stratigraphic sub-terranes; the eastern, para-autochthonous Port Nolloth Group and the western, allochthonous Marmora Terrane.

The base metal sulphides (BMS) at Rosh Pinah are contained within the approximately 30 m thick mineralized horizon, which is locally termed the ore equivalent horizon (OEH). In the Property, the Rosh Pinah Formation has been shown to be at least 1,250 m thick.

The major mineralization types are:
• Microquartzite and argillite;
• Arkose / breccia;
• Carbonate.

The Rosh Pinah deposit is hosted by a thick package of turbidites comprising hinterland and contemporaneous volcanic clastics deposited in a Neo-Proterozoic rift basin during the early part of the evolution of the Gariep Terrane of southern Namibia. Metals scavenged from a primary argillite mineralization were concentrated by late hydrothermally driven carbonate alteration, providing a carbonate host. Basin inversion led to oblique continental collision and complex deformation of the deposit, resulting in two phases of disharmonic overfolding with associated faulting and shearing.

The deposit is consequently presented as a series of discrete car ........

Current mining method
Rosh Pinah is an existing operating underground mine with well-established mining methods. The current mining method is LHOS without backfill using a Primary, Secondary, and Tertiary top-down extraction sequence. Mining using this LHOS method since 1969 has resulted in significant voids within the historical and currently mined zones.

Ore is sourced from six steeply-dipping zones, with an increasing proportion sourced from the WF3 and AAB zones, as the eastern zone (EOF) and southern-central zone (SF3, SF3, and BME) are depleted.

Access to the production areas is via multiple interconnecting declines that provide fresh air intake into the mine. A new independent decline from surface to the WF3 zone is proposed.

The current mining areas use a LHOS Primary / Secondary extraction sequence with no backfill, except for WF3, which uses a LHOS Primary / Secondary / Tertiary extraction sequence with no backfill.

The current mining fleet consists of mechanized mobile and ancillary fleet including development jumbos, production drills, loaders and 30 t trucks for haulage to an underground crushing and conveying system (notionally called the Krupp). Future plans include the use of 60 t trucks to haul WF3 material directly to surface.

Current ore haulage is via a decline to the Krupp tip point comprising three ore silos in which to tip. Blending of the ore is conducted using the ore silos to maintain a cons ........

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The Rosh Pinah processing plant, which has been in continuous production since 1969, uses similar proven technologies to most other lead-zinc base metal beneficiation circuits. It currently comprises of crushing and grinding followed by sequential flotation to produce separate lead and zinc concentrates. Rosh Pinah currently treats 0.68 to 0.71 Mtpa and produces circa 40 to 60 ktpa of zinc as flotation concentrate and circa 4.5 to 7.5 ktpa of lead as flotation concentrate.

The process includes conventional size reduction and mineral beneficiation unit processes. The current process plant includes the following unit operations:
• ROM ore feed tip (located underground);
• Primary crushing (located underground);
• Screening;
• Secondary crushing;
• Tertiary crushing;
• Stockpile and reclaim;
• Single stage ball milling with classification cyclones;
• Lead rougher and scavenger flotation;
• Lead concentrate regrinding and cleaner flot ........