(April 25, 2018, 2:33 PM EDT) -- WILMINGTON, Del. — Unable to resolve their dispute over a $1.6 million tax refund through mediation, the Internal Revenue Service and reorganized chemical conglomerate W.R. Grace & Co. agreed April 2 on a briefing schedule for the IRS’s appeal in Delaware federal court of a bankruptcy judge’s ruling in favor of W.R. Grace (In re: W.R. Grace & Co., et al., United States v. W.R. Grace & Co., et al., No. 17-cv-1588, D. Del.)....