By Timothy Puko Natural-gas futures closed at a six-month low Thursday after a weekly stockpile report showed a greater surplus than expected. Prices for the front-month August contract settled down five cents, or 1.2%, to $4.12 per million British thermal units on the New York Mercantile Exchange. It was a fourth-straight declining session, part of a month of losses that cut prices by 13.5% since June 12. Producers added 93 billion cubic feet of gas to storage for the week ended July 4, the U.S. Energy Information Administration said. The addition was 1 billion cubic feet larger than what analysts and traders had expected and 21 billion cubit feet larger than the five-year average addition for that week of the year. Beating the five-year average addition is an important measure of progress. Producers need to beat average storage additions by 20 to 35 billion cubic feet each week for […]