U.S. stock futures were lower this morning, with the Dow futures falling around 0.1% on Tuesday.Shares of Hallador Energy Company HNRG fell sharply in today's pre-market trading following a fourth-quarter sales miss.Hallador Energy reported quarterly earnings of 7 cents per share which beat the analyst consensus estimate of a loss of 13 cents per share. The company reported quarterly sales of $94.200 million which missed the analyst consensus estimate of$95.450 million.Hallador Energy shares dipped 6.8% to ...