Copper mining and smelting in the Sohar Region of Oman has a history dating back to the Bronze Age. Weathered, outcropping VMS deposits provided a major source of metal for early Bronze Age cultures in Mesopotamia. Copper metal continued to be sourced from the region right through the Middle Ages and during the rise of Islam.
The similar geological character of the Semail Ophiolite in Oman to the Troodos Massif in Cyprus, stimulated the first round of modern mineral exploration and mining in the region. It was in the 1950s and 1960s that local and international companies began serious copper mining in Cyprus. Success in Cyprus brought enquirers to Oman to first assess the copper potential of the Semail Ophiolite in Oman.
Between the 1970s and 1990s the Oman Government sponsored international aid-orientated and commercial mining groups to conduct basic geological mapping and more focussed systematic mineral exploration for copper in the Semail Ophiolite Belt. Early geological mapping of the belt was conducted by both the BRGM and the British Geological Survey. Standard prospecting and reconnaissance methods were successful in locating the more obvious old workings and surficial deposits, leading to the identification of some 150 sulphide-bearing prospects along the 600 kilometre strike of the Belt. Certain prospects were selected for more detailed ground geology, geochemical and geophysical surveying, with the drill testing of the most promising targets. This intense period of multinational exploration resulted in the discovery of more than 44 million tonnes of 1-2% copper.
The first mover, Canadian junior, Prospection Ltd., conducted extensive airborne geophysical, and ground geochemical and geophysical surveys across the full 600 kilometre strike of the ophiolite belt over several years. Their work identified more than 200 geophysical and geochemical targets for follow up.
Of the 25 major prospects in the Belt, the Oman Government selected three adjacent deposits for mining -- Bayda, Lasail and Aarja -- and commenced construction of a concentrator, smelter and refinery complex to beneficiate the ores. Production by the state-owned Oman Mining Company (OMCO) mined some 14 million tonnes of predominantly stringer ore during a period of high copper prices between 1983 and 1994. As copper prices fell, OMCO ceased mining but continued to operate the Lasail concentrator-smelter-refinery complex by processing imported copper concentrate.
Post-1980, the Oman Government sponsored further regional exploration through the state-owned company OMCO and by the Japanese International Cooperation Agency (JICA) with the Metal Mining Agency of Japan (MMAJ) and Bishimetals. The fairly intensive JICA work program was conducted in three phases over several years between 1995 and 2000 with an emphasis on just a few areas of known or identified mineralisation. This stage of work led to the discovery of two mineralised districts: firstly, Hayl-al-Safal -- Rakah -- where 17 million tonnes of 1.2% copper and 1.0g/t gold massive sulphide and stringer-stockwork material was discovered associated with five outcropping gossans, and secondly, Ghuzayn where the drilling of geophysical anomalies resulted in the discovery of 14 million tonnes of 1.4% copper in at least three blind deposits at depths of 100m to 250m below surface. This phase of exploration focused on broad ground-based Induced Polarisation (IP) chargeability coverage with only selective, much smaller, Time-domain Electro-Magnetic (TEM) followup over the best IP anomalies. Only coincident IP and TEM anomalies were drill tested. As chargeability IP responses are largely related to vein and disseminated sulphide accumulations, virtually all the deposits located in this phase of work are stringer, stockwork type with grades between 1.0-1.5% copper. From an exploration stand-point, the amount of drilling done was relatively small with only 38 holes drilled for 9,657m over the five year period. Of this, 71% of the drilling - 27 of the 38 holes - were drilled in the Ghuzayn area alone.
Relatively little modern exploration has been carried out in Oman since the 1980s and 1990s. Consequently, the newest exploration techniques developed to search for covered VMS deposits have not been applied widely. Furthermore, much of the early work was not captured in digital format. Initiatives by the Ministry of Commerce and Industry (MCI) in Oman and through the private company Kenex Knowledge Systems are seeking to re-dress this, with new digital databases being formed, which are seeking to capture all previous exploration information.
A new phase of copper exploration and mining commenced in the early 2000s when a local Omani firm, Mawarid Mining (formerly known as the National Mining Corporation -- NMC), was granted exploration blocks (Blocks 1, 2 and Ghuzayn) and commenced exploration. Surface mapping and gossan identification led to the early discovery of five deposits totalling 3.5 million tonnes of 3.0% copper -- Shinas at 2Mt @ 2.0% Cu and a small cluster of bodies at Hatta with 1.5Mt @ 3.5% Cu. In 2005, Mawarid purchased the concentrator section of the Lasail concentrator-smelter-refinery complex from the government company OMCO. Open pit mining commenced at Shinas & Hatta in October 2007 with the plan to treat one million tonnes of ore per year through mining and trucking the ore some 80 kilometres south to the Lasail Beneficiation Complex.
It is important to notice that Mawarid is mining material with a head grade of between 2.5-3.0% copper, nearly double the grade mined by OMCO in the past. This is because Mawarid have been successful in discovering the higher grade massive sulphide components of the Oman VMS deposits and not the stockwork, stringer zones that OMCO mined in the past.
Photos of Oman's mining industry -- supported by a well-developed infrastructure of roads, harbours, hydro-electric power and other facilities
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