(December 20, 2017, 1:50 PM EST) -- WILMINGTON, Del. — The Internal Revenue Service and reorganized chemical conglomerate W.R. Grace & Co. must mediate the IRS’s appeal of a bankruptcy judge’s ruling awarding the company an additional $1.6 million tax refund, according to a minute order entered Nov. 22 in Delaware federal court (In re: W.R. Grace & Co., et al., No. 17-cv-1588, D. Del.)....