African Mining January - February 2019 | Page 37

Hard issue Trekkopje under care and maintenance Trekkopje construction nearing completion in 2010. French company Orano Mining Namibia, previously Areva Resources Namibia (the company changed its name in January 2018), acquired a mining license to develop the Trekkopje uranium mine in 2008. The mine was poised to become the tenth-largest uranium mine in the world. The estimated life of mine was 12 years. Construction got under way and the mine was nearing completion, on target to start production in 2011, when disaster struck at the Fukushima nuclear power station in Japan (the mine and plant actually completed a test run in 2011). Production was planned for that same year. Fukushima pulled the rug from the uranium market’s feet, and Trekkopje postponed production until the jitters settled down. The uranium price, however, tanked and continued its slide to rock bottom. Since then, it has recovered somewhat, but not enough to ensure Trekkopje’s profitability. More than eight years later, this promising project is still on care and maintenance. Trekkopje was going to use a heap leach method to extract uranium, which requires a lot of water that is not readily available in the desert. The desalination plant was built for one specific reason: to ensure a continuous supply of good quality water to the mine. The water produced by the plant would be carried across the desert to Trekkopje by a 48-km pipeline measuring 800mm in diameter and equipped with three pumping stations. A 132kV power line was also built along the pipeline to supply electricity to the plant. At peak activity, the mine was expected to use about 12 million cubic metres of water, so there was always going to be approximately eight million cubic metres surplus, which would have been available to industrial and domestic users in the Erongo region. So, when Trekkopje never actually started producing uranium, the town of Swakopmund, various mega uranium mining operations, and, most of all NamWater, were presented with a very welcome surprise. At any time, 20 million cubic metres is available for other users, and mines like Husab and Rössing are major beneficiaries. In fact, Husab’s fortunes are totally dependent on the water provided by the desalination plant. The mine started operating about four years ago and has been using water produced at the Erongo plant since day one of operation. www.africanmining.co.za Mining in extreme environments like on the Namibian west coast, which experiences four seasons in one day, requires constant maintenance to preserve plant and equipment. This is the case when actively mining, but even more so when a mine has been placed on care and maintenance, like Trekkopje was in 2013. Although Trekkopje has never produced saleable product, the mine and plant are fully functional, and it has to remain in working condition. All structures built on the mine are protected and can be commissioned when required and at minimal cost. The C & M team of 20 people work according to maintenance schedules that have been captured on the Pragma software program. The Pragma database contains all structures and equipment with the manufacturers’ specifications and maintenance requirements. The system generates job cards, schedules work in progress, and produces monthly reports, for example on maintenance statistics, labour hour distribution or completion of schedules. General C & M tasks include proper storage, lubrication, corrosion protection, and functionality checks. In addition to the scheduled work, some special projects were carried out in 2015. In October 2015, the engineering team successfully optimised overhead line insulator cleaning operations by adding linseed oil to Tectyl 506, a product already used to combat the corrosion of this equipment. The cleaning and protection of over 60 000 conveyor idlers is a major task that will be repeated annually. Cleaning and protection of dust collector ducts at the crushers were completed. Protection of pumps, valves, and gauges is achieved by cleaning them with a mixture of soluble oil and water under high pressure, followed by a spray-on coat of Tectyl soon after drying. The Maxi Stock Integration Project was completed in July 2015. All equipment and parts stored in the logistics yard were catalogued by data classification and stock coding and stored in containers for protection from the elements. JANUARY - FEBRUARY 2019 AFRICAN MINING 35