By Reuters Staff 2 Min Read TORONTO (Reuters) - Benga Mining Ltd, which aims to build a steelmaking coal mine in Canada’s Rocky Mountains, on Monday said it would launch an appeal after an expert panel last month rejected the proposal on environmental grounds. A joint federal and provincial panel in June found that the likelihood of significant adverse environmental effects on water and wildlife resulting from the Grassy Mountain steelmaking coal mine outweighed economic gains. Privately held Benga Mining is a unit of Riversdale Resources, owned by Australian billionaire Gina Rinehart’s H...