It has been a tough year for investors in Talvivaara Mining, the FTSE 250 listed owner of a Finnish nickel mine. As if a 29% drop in the nickel price in the past six months and a series of plant stoppages in April and May weren't bad enough, the company delivered a triple whammy of bad news.

Shares tumbled by a fifth at the end of last week, after Talvivaara cut its output guidance, warned of a strike and announced the surprise resignation of CEO Mr Pekka Pera.

Talvivaara relies on an unusual mode of production known as bio-heap leaching. This employs microbes and sulphuric acid to extract metals, a process which is cheaper and more environmentally friendly than conventional smelting. And until recently, the business looked fit as a fiddle, with its share price enjoying a six fold rise in 2009 and 2010 as its mine in Sotkamo, eastern Finland, produced a steadily rising stream of nickel.

But last week, Mr Pera cut his production forecast for this year to 16,000 tonnes from a previous estimate of between 22,000 and 28,000 made in May. The cut is the result of corrosion in the steel parts in generators of hydrogen sulphide needed to process the ore before smelting. Meanwhile, the threatened strike would fall between October 21st 2011 and November 7th 2011 if it materializes.

Still, it should be noted that Goldman Sachs forecasts a strong growth in the price of nickel over at least the next year, while production should rebound next year. So Talvivaara might make a good investment in the longer term. Given the recent update, however, we would keep clear for now.