Oaktree bought into DDH1 in 2017 and the driller has since acquired Strike Drilling and now Ranger Drilling in equity deals that diluted the US private equity fund manager's interest.

The latest acquisition of Matt and Julie Izett's Ranger Drilling, which they founded in 2005, gives the Izetts shareholdings in DDH1. Last year Strike Drilling managing director Richard Bennett became a DDH1 director and shareholder.

A specialised deep-drilling contractor with 55 diamond-core rigs, DDH1 added a surface iron ore drilling focus with Ranger and new exploration drilling fleet with Strike. The company recorded revenues of circa US$90 million in 2018, up 45% year-on-year, and a US$8 million net profit. It reportedly has about 700 employees.

DDH1, Ranger and Strike continue to operate independently under a bigger group structure headed by CEO Sy van Dyk since last October. van Dyk was CEO of mining contractor Macmahon Holdings in 2015-2016.

DDH1 co-founder, shareholder and managing director Murray Pollock said the company continued to assess M&A opportunities in a drilling market that remained competitive but which was seeing activity and pricing improve in Australia.

Oaktree's representative on the DDH1 board, Bryon Beath said Ranger, Strike and DDH1 all grew during the 2012-2016 mining downturn.

Canada-headquartered Brookfield Asset Management last month acquired about 63% of Oaktree in a $4.8 billion deal to create a group with about $475 billion of assets under management.