UPDATE 1-ENRC hits back at First Quantum on possible lawsuit

* ENRC rejects accusations about purchase of Congo project

* First Quantum had threatened to sue ENRC for billions

* First Quantum lost mining rights to Kolwezi copper project

(Adds details, quotes, background)

LONDON, Sept 9 (Reuters) - Kazakh mining group ENRC (ENRC.L: Quote) rejected accusations by rival miner First Quantum Minerals Ltd (FM.TO: Quote) about ENRC's purchase of a disputed copper project in Congo and said it would vigorously defend any legal action.

First Quantum (FQM.L: Quote) said on Monday it was considering legal action against ENRC seeking billions of dollars in compensation after the Democratic Republic of Congo government took away its Kolwezi licence and ENRC bought the rights. [ID:nLDE6850Y5]

"No proceedings have been issued against ENRC. If proceedings are issued, ENRC will defend its legal position vigorously," ENRC said in a statement on Thursday.

ENRC announced on Aug. 20 that it had paid $175 million for a majority stake in a company, Camrose, with licences to a range of DRC copper assets, including Kolwezi. [ID:nLDE67J1C1]

"FQM did not respond to a previous letter from ENRC, suggesting a dialogue. Instead of accepting that offer, FQM has made statements to try to discredit ENRC and to interfere with ENRC's rights to develop the Camrose joint venture and the Kolwezi tailings project," ENRC said.

ENRC repeated on Thursday that it had completed an extensive due diligence process regarding Kolwezi before buying rights to the project from a company controlled by Israeli resources investor Dan Gertler.

"The licence was withdrawn by the DRC Government in August 2009, and the Court of Appeal confirmed that the withdrawal was lawful," ENRC Chief Executive Felix Vulis said. "Any dispute that First Quantum has is with the relevant DRC authorities." (Reporting by Eric Onstad; Editing by Mike Nesbit)