Mono County drug enforcement agents seized a half-pound of methamphetamine after a sting turned into a high speed chase from Mammoth to just outside Bishop on Saturday.Hector Pacheco Jr., 34, of Ontario, Calif., was arrested after the chase which started with a drug buy in Mammoth, according to the Mono County Sheriff's Office.Drug agents conducted the buy from Pacheco and as they were about to take him into custody, he got into his vehicle and sped away, nearly striking a member of the arrest team.Spokeswoman Jennifer Hansen said that Pacheco hit a Mono County Sheriff's patrol unit that tried to …