Union negotiators and executives at Mountaineer Casino Racetrack & Resort along the Ohio River have reached a tentative deal on a new contract for 200 striking workers.The agreement was reached at 4 p.m. Monday, Mountaineer President Ted Arneault told investors and analysts during a late-day conference call to discuss quarterly earnings. Lawyers for both sides have agreed on the contract language, and a press conference was planned for later Monday evening, he said.