 KATY, Texas, April 13, 2021 PRNewswire -- U.S. Silica Holdings, Inc. NYSE: SLCA announced today that it will release its first quarter 2021 financial results before the New York Stock Exchange opens on Friday, April 30, 2021. Conference Call This release will be followed by a conference call for investors on Friday, April 30, 2021 at 7:30 a.m. 