Consideration for the acquisition was 150.7 million Ausdrill shares and $25.4 million cash.
Ausdrill said the acquisition made it the second-largest mining services company in Australia by revenue, and the leading ASX-listed pure-play mining services company.
Ausdrill managing director Mark Norwell said the company was now a lower capital intensity and higher return business.
"Barminco is a complementary business to Ausdrill, with a leading market position in underground hard rock mining that establishes the company as a more diverse group with a broader service offering sought by our customers," he said.
"Not only is it a strategically and financially compelling deal, there is a good cultural fit with the two businesses having worked together in Afric...