Arch Coal Inc. said it may file for bankruptcy in the “near term” as the company’s cash flow cannot support its $5.1 billion in debt. Arch, the secondlargest US coal producer by volume, is running out of options after it terminated a debt-exchange offer last month that would have enabled it to cut its debt. The company reported a $2 billion loss for the third quarter, due to an asset impairment charge based on deteriorating market conditions.