* Eurochem seeks $800 mln from London-listed Shaft Sinkers
* Seeks similar sum in Dutch suit from main shareholder IMR
* Claim "nonsensical and fabricated" - Shaft Sinkers
* IMR says will make robust defence
* Eurochem stands by investments despite potash price slump
By Douglas Busvine
MOSCOW, Nov 12 (Reuters) - Engineering firm Shaft Sinkers has dismissed as "nonsensical" an $800 million claimbrought by Russia's third-largest fertiliser firm over theflooding of a mineshaft that delayed a $4 billion potashproject.
The claim by Eurochem pits its owner - tycoon AndreiMelnichenko - against a trio of oligarchs from ex-Soviet stateswho indirectly control Shaft Sinkers.
Eurochem filed for arbitration in October 2012 in France andSwitzerland after terminating the contract in late 2011. It saysShaft Sinkers concealed evidence that the chemical sealants usedwould fail to keep groundwater out of the mine.
Shaft Sinkers, which is based in South Africa and listed inLondon, counters that Eurochem is motivated by a desire to avoidlosses after the collapse of a Russo-Belarussian sales cartel inJuly hammered global prices for the soil nutrient.
"I could agree with many commentators who suggest (that)given the collapse in the price of potash it is better to stopthe work, keep the potash in the ground and sue somebody," ChrisHall, chief financial officer of Shaft Sinkers, told Reuters.
The price slide may render potash investments uneconomic,analysts say, while fallout from Uralkali's exit fromthe Belarus alliance may force the sale of the Russian company,redrawing the competitive landscape.
Hall described the Eurochem claim as "nonsensical andfabricated", adding that it was "out of all proportion to thedisputed contractual issues". Shaft Sinkers declined to commenton the status of the arbitration, which is confidential.
Eurochem - seeking to become a leading global producer ofall three key soil nutrients: nitrogen, phosphates and potash -rejected Shaft Sinkers' statement as "demonstrably false".
Eurochem has launched a second case, suing Shaft Sinkers'main owner, International Mineral Resources (IMR), for a similarsum for alleged fraud in a Dutch court. IMR is wholly owned bythe founders of ENRC - Alexander Machkevitch, Patokh Chodiev andAlijan Ibragimov - and in turn owns 48 percent of Shaft Sinkers.
Kazakh-focused miner ENRC is delisting from Londonafter a buyout of minority investors led by the trio.
Melnichenko, 41, is estimated by Forbes magazine to have afortune of $14.4 billion. He owns a $300 million "megayacht"named "A" after his wife Aleksandra, a Serbian model and popstar turned society hostess.
SHAFT NOT SUNK
Eurochem in 2008 awarded a $342 million contract to ShaftSinkers to bore a 1,100-metre-deep "cage shaft" that would movemen and equipment to a seam of potassium salts at its Volgakaliymine.
The deal accounted for a large share of Shaft Sinkers' orderbook, enabling the company to float in London in 2010.
Shares in the company have slid 80 percent since the haltingof work on the shaft a year later and the start of litigation.
Volgakaliy is one of two Russian projects that Eurochem isdeveloping from scratch and wants to bring into production from2017. Combined annual potash output should be ramped up to 8.3million tonnes by 2022.
Eurochem based its October 2012 claim on the $160 million itsays it paid to Shaft Sinkers and an appraisal of the cost oflost output caused by a two-year delay. Shaft Sinkers has made a$15 million counterclaim for unpaid inventory.
The Dutch writ filed this year by Eurochem against IMRclaims that it and Shaft Sinkers were responsible for concealingan expert report that said its "grouting" method to seal theshaft would not work.
At a preliminary hearing on July 19, the Amsterdam DistrictCourt found that Eurochem's claim against IMR was well grounded,stating also that IMR effectively controlled Shaft Sinkers. Itgranted Eurochem the right to freeze IMR assets worth $1.2billion pending main proceedings in the case.
IMR declined to comment in detail but said it would make arobust defence in the main hearings on the case, for which nodate has yet been set.
CARTEL COLLAPSE
Eurochem has since restarted work on the Volgakaliy cageshaft and says it is committed to commissioning its two Russianexpansion projects - the other is the Usolskiy project in thePerm region - on schedule by 2017.
"These are very important long-term projects for Eurochem aswe continue to pursue our strategy to become one of the fewglobal players present in all three nutrients - nitrogen,phosphates and potash," Eurochem spokesman Vladimir Torin said.
Torin dismissed suggestions that Eurochem's Russian projectswere at risk from price declines resulting from the exit byUralkali from the Belarussian cartel that had controlledtwo-fifths of world potash sales.
Uralkali is unconnected to the Eurochem legal battle. Itsmain owner, Suleiman Kerimov, has declined through hisinvestment firm to comment on reports of a possible Uralkalisale.
Sector analyst Boris Krasnojenov, of Renaissance Capital inMoscow, has forecast that Uralkali's sale prices to China, on acost-and-freight basis, will fall to $300 per tonne in 2014 from$350 this year and $470 in 2012.
"No price collapse has occurred," Torin said. "TheVolgakaliy project is not scheduled to commence commercialproduction until mid-2017, by which time it is expected thatpotash prices will have further increased."
