Overview
Status | Care and Maintenance |
Mine Type | Underground |
Commodities |
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Mining Method |
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Processing |
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Otjihase consists of two underground mines (Otjihase and Matchless) and an 800ktpa copper concentrator, currently on care and maintenance. The operations were in production until September 2015, producing high quality concentrate sought after for blending. |
Summary:
The Matchless Amphibolite Belt is a conspicuous narrow northeast-southwest trending sequence consisting of amphibolite, chlorite-amphibole schist, talc schist and metagabbro which extends over a distance of 350km in the Southern Tectonostratigraphic Zone of the Damara Orogen. The Matchless Belt represents a sequence of metamorphosed tholeiitic basalts, which are the product of submarine volcanism. Stratigraphically the Matchless Amphibolite Member occurs within the Kuiseb Formation (Khomas Subgroup) of the Damara Sequence, which is a metapelitic sequence of biotite schists, with subordinate calcsilicate rocks and carbonaceous schists.
The Matchless deposit comprises six echelon shoots namely the Eastern Prospect, East Shoot, West Shoot, River Shoot, Western Prospect and Western Extension, extending over a strike length of 2.5km from the east to the west in that order (Fig.3.3.1_1). The East Shoot, West Shoot and River Shoot form the old Matchless Mine. The mineralisation occurs in amphibolites and quartz-sericite schist lying between the Matchless Amphibolite and the Footwall Amphibolite, dipping at 30o , 350o towards the north and plunges to the northwest. The mineralised zones are distinct pyrite chalcopyrite occurring in a quartz mica schist. A slight angular discordance between the mineralised zone and the Matchless Amphibolite was mapped on outcrop. The mineralisation is strata-bound and is of a massive sulphide type containing mainly pyrite, pyrrhotite, chalcopyrite and minor sphalerite, gold and silver.
Summary:
A shoot called Matchless Western Extension, some 1,800m west of the old Matchless mine, was being mined by means of a decline that reached 11 Level. The shoot has a steep plunge to the northwest and the deposit dips at 35° to 45° which requires the decline to progress rapidly down dip.
Previously, the Matchless mine was operated successfully by a mining contractor using a cut and fill mining method. The planned mining method is a cut and fill method utilising 3.0m high lifts.
Source:
Summary:
Ore from the Otjihase mine will be crushed underground through a jaw crusher to a nominal 150mm prior to being transported to surface, to a 3,200t receiving bin at the plant. Ore from Matchless mine is road hauled and similarly crushed at Otjihase ahead of the same receiving bin. The receiving bin has 14 off take points feeding a single conveyor.
The crusher plant consists of a primary grizzly with oversize being crushed in the 5½ft Standard Symons secondary crusher. The grizzly fines are screened on a vibrating screen to reduce the load on the tertiary crusher. The screen oversize and the secondary crusher product are conveyed to a surge bin then to the tertiary screen and tertiary crusher, a 5½ft Shorthead Symons.
The milling circuit consists of three closed circuits Vecor 10ft x 12ft ball mills with 20” hydrocyclones. Mill motors are 670Kw with 11Kv supply. Historically the grind was approximately 80% passing 250 micron. The milling circuit configuration is ve ........

Combined production numbers are reported under
Central
Reserves at December 31, 2014:
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven & Probable
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289,190 t
|
Copper
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1.83 %
|
5,295 t
|
Indicated
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280,224 t
|
Copper
|
3.14 %
|
8,796 t
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Inferred
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230,460 t
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Copper
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2.32 %
|
5,346 t
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