Arch Coal Profit Off, But Coal Sales Up  NEW YORK (Reuters) - Arch Coal Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=ACI.N target=/stocks/quickinfo/fullquote"&gt;ACI.N&lt;/A&gt;, the  second-largest U.S. coal producer, said on Friday that  third-quarter profit fell slightly as rail disruptions and  hurricane-related work delays affected mining operations.