* Court says documents are material to Cilins' defence
* BSGR says welcomes development
* Guinea to decide within a month on BSGR concessions
By Silvia Antonioli and David Rohde
LONDON/NEW YORK, Jan 16 (Reuters) - A former advisor to mining company BSG Resources being held in the United States in connection to a bribery investigation involving mining concessions in Guinea has been granted permission by a U.S. judge to prove that documents related to the charges against him are forgeries.
Frederic Cilins, a French national who used to represent BSG Resources (BSGR), was arrested in Florida in April on charges of obstructing a criminal investigation, tampering with a witness and attempted destruction of documents sought by a grand jury.
The U.S. is investigating potentially illegal payments made to Guinean officials and to Mamadie Toure, a wife of the deceased former president Lansana Conte, to obtain mining concessions for BSRG in Guinea, and transfers of those payments into the United States.
The outcome of the investigation could influence Guinea's decision on whether to strip BSGR, the mining arm of Israeli billionaire Beny Steinmetz's business conglomerate, of the rights to develop a portion of Simandou, one of the world's largest untapped iron ore deposits.
Cilins claimed the documents, which include contracts and records of payments and gifts to Toure and Guinean officials, are forgeries.
The U.S. government had claimed the authenticity of the documents was inadmissible as evidence because it was irrelevant to the obstruction charges.
U.S. District Judge William H. Pauley III said in a court ruling on Wednesday that the documents can be tested as they are material to Cilins' defense.
"To the extent Cilins can test the original contracts' authenticity without destroying them, he may do so," Pauley said. "If Cilins believes that destructive testing is required, he may make a further application to this Court."
A spokesman for BSGR said the company welcomes the latest development in Cilins' case.
Guinea is currently carrying out a review of how the company obtained the mine and its results are expected to be made public within a month.
BSGR has vigorously and repeatedly denied the allegations of wrongdoing and has in the past said it believes the committee's procedure to be "fundamentally unfair." (Editing by Marguerita Choy)