(See our Education section) BHP is down 1.16 percent to $48.48 in afternoon trading after dipping below $48 earlier today for the first time in more than five years. A producer of such materials as oil, coal, iron ore, and copper, BHP has been hurt by weak global growth and tepid inflation. Overall option volume in BHP is nearly double its full-session so far today, with those December 47.50s accounting for more than half the total.