(ShareCast News) - Shares in AIM-listed miner Goldstone Resources dropped nearly 12% on Thursday morning after it was revealed that a former director made a large cash claim against the company over his termination.The sum sought would be a "significant proportion" of the company's current cash resource.The former employee made a claim in the Labour Court of South Africa for sums concerning the termination of his employment at the miner.In September, the company reported that it had cash assets of around $80,000 for the six months ended 30 June.Goldstone Resources said it is considering the allegation with its legal advisers and plans to "robustly defend the claim".Shares in Goldstone Resources were down 11.56% to 1.99p at 1039 BST.