Terrible Accident. Mr. James Wallace, who was at work on the Ohio Co's claims at Moore's Flat, was killed on Monday last. He was engaged in picking out an old blast, and as he picked into the powder, it exploded, mangling him in a horrible manner and killing him instantly. Mr. Wallace leaves a wife and seven children, who reside at Mineral Point, Wis. Nevada Democrat (Nevada, California) Jan. 20, 1858