58 www. bus- ex. com March 10 zinc plant over the next three years. The first phase of expansion at the plant is a ? 43 million investment in grinding, flotation and filtering equipment, which will double the processing capacity to one million tons a year. This is due to come online in the second half of next year. " All the equipment and building space in this first phase of expansion has been designed to enable us to ramp up easily to a second phase of expansion. The plan is to double our capacity once again to two million tons of zinc ore by 2013, and this will make us one of the biggest zinc producers in Europe," Andreatidis says. " We are currently in the last stages of the pre- feasibility study for this. There will also be some minor infrastructure upgrades to do, and we will need to purchase more equipment such as flotation cells and vertical grinding mills." The mine itself has a single 600 metre- deep access shaft, so from the surface its footprint is modest. The shaft head, processing plants, rail head and stockpiles occupy only around 160 hectares and the tailing area another 170 hectares. Underground, however, there are currently over 140 kilometres of galleries spread out in a flat configuration along the plane of the pyritic lens. " We mine our ore principally from the Corvo deposit to the east of the shaft and the Neves deposit to the west, at the moment," Andreatidis says. " However, we are developing the Lombador South deposit, which is to the north of Corvo. This contains rich zinc and copper resources and should be producing in the next few years." Further north lies the Lombador North deposit which Somincor is continuing to explore. " We've put some exploration holes through there and found copper intersections at 1,200 metre depth- some of 22 metres with 5.9 per cent copper, and others of 32 metres with 3.8 per cent copper. So there are still large copper lenses out there. Our aim is to define how much copper we have in those deep areas and to begin mining it, five or six years from now. But it's early days yet, and we may need a new shaft because it's so deep and so far to the north of the existing ore haulage systems." Zinc exploration, meanwhile, has been put on hold- not because of the low zinc prices but simply because so much has already been found and is yet to be developed. Expansion of capacity at the Neves- Corvo site has been a relatively inexpensive and easy exercise, partly because of the existence of the old tin plant and equipment; and partly because the site enjoys easy access to all the utilities. Water and appropriate recycling technologies give plentiful supply and are adequately sized, and power comes via a 150 kilovolt power line directly from the country's main transmission artery. The mine is also located close to the main A2 highway that links Lisbon to the Algarve, and this means it's within easy reach of the airports of Faro, 80 kilometres to the south and Lisbon, 150 kilometres north- west. The main bulk transport is by rail. The mine has its own rail spur and transports copper and zinc concentrates directly to its ship loading facilities at the Atlantic port at Setubal, about 140 kilometres away. Andreatidis points out that the company has not focused purely on exploration and development, but has also been considering the eventual closure and rehabilitation of the site. Tailings from the mine, which are highly pyritic and oxidise to form acidic waste when exposed to air, have so far been disposed of by the conventional method of depositing them under a one metre skin of water- in this case, in a purpose built dam close to the mine. " The idea was that the water cap isolates the tailings from oxygen, preventing them from becoming acidic and leaching into the water table. However, we felt that was not a good legacy to leave following closure! How do you maintain a water cap forever?" he asks. " We also had to find a way of extending the life of the dam, as a tailings dump, for another 20 years." To solve this problem, the company has been engaged in a 10- year research programme in partnership with Golder Associates, to adapt the Golder Paste Technology to pyritic tailings. After feasibility studies, detailed engineering and extensive pilot testing at the mine site, a ? 20 million paste plant is now under construction and is due to come online in the second half of this year. Over the next 20 years, a series of cells will progressively be constructed across the dam. Each cell will be filled with tailings and then covered with paste. As the paste pushes the skin of water out of the cell, it encapsulates the tailings in a moist layer that excludes oxygen. When the cell is full, it will be capped with a layer of rock, a " All the equipment and building space in this first phase of expansion has been designed to enable us to ramp up easily to a second phase of expansion"
Somincor construction going on we now have over 800 contractors on site, in addition to our own 850 staff." Yet 2009 saw the lowest accident rate on record for staff and contractors combined, and broke many records for health and safety. " We achieved an all- time low of just two lost time accidents in the entire year for our own staff. We only had eight medical treatment accidents- the previous record was 11- and our total accident frequency rate for our own staff came down from a previous low of 2.8 in 2007 to 1.69." Sixteen years ago, when Somincor produced its first ' life of mine' plan, it was based on the known reserves at that time which suggested the mine would be finished by 2012. This intensive programme of exploration and development has significantly prolonged that life expectancy. The full extent of the copper and zinc finds have yet to be defined, so it is hard to predict the lifespan of the mine, but there is no doubt that it has an impressive future, based on a combination of copper and zinc mining. - Editorial research by Daniel Finn March 10 www. bus- ex. com 59 geomembrane, then sand and finally, bentonite. " We will then cover this with soil and grass it over," Andreatidis explains. " In 20 years the dam will look like the rest of the countryside- a little rolling hill. And the tailings will be sealed from oxygen and shouldn't form acid. It's turned out to be an economically sound and environmentally good solution for us. We're happy with that." Mining has always been a notoriously hazardous business. However, Lundin Mining has invested considerable time and effort in addressing health and safety. This has been done from three angles. " Good communications are absolutely essential," Andreatidis says. " We have also developed clear standards and guidelines for all activities on site, and we've put increasing efforts into training." Risk management, inspections and auditing have become much more rigorous and have extended to contractors on site. " We have record levels of staff here at the moment," he continues. " With the increased mining activity and the