* Company struggling to recover from previous leak
* Had raised 261 mln euros in rights issue last month
* CEO says likely no financial impact this year
* Shares fall 17 pct, hit lowest ever (Updates with authorities' new estimate on leak size)
By Jussi Rosendahl
HELSINKI, April 8 (Reuters) - Talvivaara has halted production at a nickel plant in eastern Finland aftera further waste water leak, hammering its shares just a monthafter it launched a multi-million euro cash call.
Shares in Talvivaara, which is still recovering from anearlier leak in November, fell more than 16 percent to a recordlow on fears the debt-burdened group will need more time andmoney to fix the Sotkamo mine's problems.
Talvivaara, which raised 261 million euros ($339.9 million)from investors in March to help finance the mine's development,had been hailed as a pioneer in the use of bacteria to extractnickel - a process called bioheap leaching - but the mine hasbeen hit by environmental problems.
The new leak was found late on Sunday, the Kainuu Centre forEconomic Development, Transport and the Environment said. Itraised its estimate for the leakage from the mine's waste waterpond to around 7,000 cubic meters per hour, having initially putthe loss at between 2,000 and 3,000 cubic meters.
The company - which finished last year with net debt of 564million euros, giving it a debt-to-equity ratio of 184 percent - confirmed the leak but said waste water was not expected toflow outside the mine area as a sufficient safety dam was inplace.
Chief Executive Pekka Pera told Finnish news agency STT hedid not expect the leak to affect the firm's finances orproduction targets this year.
The November leak halted the plant's metals production forthree weeks and the extra costs forced the company to lower itsoutlook for this year.
MUCH TO PROVE
Talvivaara's mining and crushing operations have also beenhalted since September due to problems related to excess water.The company has forecast such operations would restart in Julyand a spokesman said on Monday the leak would not affect thisschedule.
But analysts said the latest incident did not bode well forthe company's plans to step up production on the basis ofreceiving the necessary permits later this year.
"Thinking of what happened last year, it could take quite awhile before they get the permits to restart the plant," saidanalyst Antti Kansanen at brokerage Evli in Helsinki.
Kansanen also noted the company had much to prove toinvestors who recently agreed to stump up for a rights issuelast month to keep the mine running.
"The company must demonstrate that they have their processunder control. This situation gives quite a contraryimpression," Kansanen said.
The company previously said it would produce around 18,000tonnes of nickel this year, far lower than its longer-term peaktarget of 50,000 tonnes per year.
"There is always a reason for concern with this type ofnews. Water treatment is an integral system for them. It mustwork," said Handelsbanken analyst Fredrik Agardh.
The Helsinki-listed stock closed down 16.9 percent at 0.1599euros, after falling as low as 0.1555.($1 = 0.7679 euros) (Editing by Helen Massy-Beresford and David Holmes)
