Heaping up riches Talvivaara

HEAPING UP RICHES

The Talvivaara Mining Company has a large mine in Eastern Finland and mines nickel and zinc. Joseph Altham spoke to Harri Natunen, Talvivaara’s CEO, to find out how the company has succeeded in exploiting its abundant reserves of nickel with the aid of an unusual and innovative technology.

The Talvivaara mine, located near the town of Sotkamo, has some of the biggest reserves of nickel outside Russia. Occupying a huge site, 60 square kilometres in area, Talvivaara has two deposits, Kuusilampi and Kolmisoppi, with total resources of 1.55 billon tonnes of ore. The mine’s resources contain some 3.4 million tonnes of nickel and 7.6 million tonnes of zinc. The Geological Survey of Finland started to explore the Talvivaara area back in the late 1970s, but for decades the deposits remained unexploited.

In 2004, the Talvivaara Mining Company obtained the right to mine these deposits and managed to produce the first metals from the mine four years later. The mine yielded over 16,000 tonnes of nickel in 2011. Now Talvivaara is endeavouring to ramp up production, with a view to producing as much as 50,000 tonnes of nickel per year along with 90,000 tonnes of zinc. On this basis, Talvivaara could eventually become capable of producing some 2.3 per cent of the world’s annual nickel supply. The Talvivaara mine is not only a valuable asset, but has also created employment opportunities for the people of the Kainuu region. “We have 500 employees,” said Mr Natunen, “and we provide work for another 400 people in outside companies that we have contracted to help us.” Bioheapleaching

If the Finns discovered more than 30 years ago that there were substantial deposits of base metals at Talvivaara, then why did they wait until the 21st century before opening the mine? Part of the answer, as Mr Natunen explained, comes down to money. Originally, the owner of the mining rights at Talvivaara was the steel firm, Outokumpu. However, Outokumpu decided against developing the mine and sold off the mining rights in 2004 instead. “We have to keep in mind that when Outokumpu studied the mining possibilities in the 1980s, the price of nickel was lower.” Nickel is now more expensive, making the mine economically viable.

Another reason why the situation has changed is that Talvivaara can now take advantage of a new technology known as bioheapleaching. Talvivaara uses bioheapleaching to recover nickel and zinc from the ore, along with smaller quantities of cobalt and copper. The distinguished Finnish scientist, Marja Riekkola-Vanhanen, was responsible for developing this technique. Bio-leaching uses the catalytic action of bacteria to promote a chemical reaction that causes the metal sulphides present in the ore to be oxidised into soluble compounds.

First, the ore must be extracted from the ground, in open-pit mining. Then the ore is crushed into small particles, eight millimetres in diameter, and stacked onto a large heap, eight metres high. Inside the heap, bacteria stimulate the separation of the metals from the ore. Bio-leaching occurs naturally in the presence of air and water, but Talvivaara speeds up the process, irrigating the heap with a circulating solution containing water and sulphuric acid and using fans to ensure the airflow. The particles are moved in a continuous cycle from a primary heap to a secondary heap for further leaching. Finally, the pregnant solution from the heap is piped down to the final stage of the production process, metals recovery. Here, using hydrogen sulphide, the leached metals are precipitated in order to reduce them into metal sulphides. “Heap leaching is commonly used in copper mining. We have been able to transfer the technique to zinc and nickel. Although there was a concern about whether the process was possible in cold winter conditions, bioheapleaching actually generates a lot of heat and we have proved that it works.”

Markets

Talvivaara has secured a 10-year contract for the sale of its entire output of nickel and cobalt to Norilsk Nickel Harjavalta, a nickelrefining plant that is a subsidiary of the Russian company, Norilsk Nickel. Talvivaara also has a long-term agreement to supply zinc to the Belgian metals business, Nyrstar. Mr Natunen acknowledged that the contracts helped Talvivaara to raise capital. However, with or without these contracts, he is convinced the overall prospects for the mine are favourable, since demand for nickel is set to remain high. “Nickel is used to produce stainless steel, and steel usage is expected to grow.”

Ambitions

Talvivaara’s expects to boost production of nickel in 2012 to at least 17,000 tonnes, although its aim is to reach a level of 25,000 Ni tonnes annualised production rate by the year’s end. However, this is by no means the only task Mr Natunen has set himself. This year, the company is investing over €13 million in environmental technology. The investments include a water-treatment system to improve the quality of effluent waters. “The level of sulphates in waste water has been higher than anticipated. We had to solve this.” Talvivaara is also planning to produce uranium as a by-product of the bioheapleaching process. The company intends to construct a uranium extraction facility and hopes to produce as much as 350 tonnes of uranium per year. Talvivaara is the first mining company to use bioheapleaching to produce nickel on a commercial basis. For Mr Natunen, running a company in this unique position is an exciting challenge. n