March 6 (Reuters) - U.S. minerals and materials group, AMCOL International, has given Paris-based Imerys four working days to match a rival bid by Minerals Technologies, which AMCOL's board has deemed superior.
Minerals Technologies raised its offer to $45.75, valuing AMCOL at $1.48 billion, on Thursday morning. This was 50 cents higher than Imerys' bid on Tuesday.
"If the revised (Minerals') proposal continues to constitute a superior proposal after the expiration of the waiting period, the company expects to terminate the Imerys agreement and enter into a binding definitive agreement with MTI," AMCOL said in a statement.
Minerals Technologies and Imerys are both bidding for Amcol, which has large reserves of bentonite - a key mineral used in the construction and energy industries.
AMCOL said it continues to favour a deal with Imerys.
Minerals Technologies has hiked its offer twice this week, first to $45 and now $45.75, after AMCOL accepted Imerys' sweetened takeover offer for $42.75 per share last week.