"Mintek Res Dig" is not a word, and therefore there can be no antonyms for it. It is possible that the phrase is actually a combination of three separate terms - "Mintek," a South African mining and metallurgy company, "Res," an abbreviation for "research," and "Dig," meaning to excavate. In this case, antonyms for the various terms would be as follows: for "Mintek," competitors such as Anglo American or BHP Billiton; for "Res," terms such as "neglect," "ignore," or "abandon"; and for "Dig," "fill," "bury," "cover," or "seal.