(ShareCast News) - Shares in Frontier Resources plunged over 10% on Tuesday, after the oil and gas explorer said it raised additional funds via a share placing.The group, which had placed shares to raise £205,000 on 17 July, raised a further £148,413 after issuing 42.4m shares at 0.35p each.In a short statement, the group said the proceeds from both placings will be used to provide additional working capitals while it continues to seek a partner for a farm-out deal of some of its projects in Oman and Namibia.The group, which owned almost £400,000, mostly because of delayed salary payments, to chief executive Michael Keyes, has written off £108.9m and settled £54.4m of those debts by issuing 5.6m to Keyes and finance director Barbara Spurries, who was owned £40,000.The remaining £272,224 will be paid if the company manages to secure a farm-out deal, which would see Frontier recoup at least £435,556 in historic exploration expenditure.Frontier shares were down 11.33% to 0.399p at 1202 BST.