Bentonite prices remain flat despite oil market woes 15 April 2015 Suppliers of drilling clay mineral stand firm over offers as buyers push for cheaper deals. Read More. Imerys closes €525m acquisition of bentonite producer SB 02 March 2015 Imerys' acquisition of Greece's SB has now drawn a line under its search for a bentonite producer. The group had previously shown an interest in US bentonite .