The slab of 70.81 million shares, representing the entire...

The slab of 70.81 million shares, representing the entire stake, was sold yesterday morning for A40c per share, or $28.3 million.

It has been confirmed that contractor-miner Mineral Resources bought the bulk of the stake and will become a major shareholder in Venturex.

While MinRes doesn't currently have any copper exposure, Venturex's shovel-ready Sulphur Springs project is only about 30km from MinRes' Wodgina lithium project in the Pilbara.

MinRes is also one of the most active mining contractors in the Pilbara.

Northern Star first invested in Venturex in 2012 as part of a plan to jointly develop the company's Pilbara copper-zinc projects.

Northern Star went on to make a string of large gold mine acquisitions, but has remained a supportive shareholder of Venturex through the years.

Last month, it was announced Northern Star executive chairman Bill Beament was leaving the gold miner to lead a recapitalisation at Venturex.

Subject to shareholder approval, Beament will contribute up to $37.3 million of a $58 million raising.

Beament will formally join Venturex as an executive director from July 1, but will consult to the company until then.

Former Detour Gold CEO Mick McMullen has joined as executive director, but will revert to non-executive director from July 1, while lawyer Michael Blakiston will become chairman.

Venturex is working on pre-construction activities at Sulphur Springs with the aim of moving to a final investment decision as soon as possible.

Drilling will begin in May, focused on upgrading the 1.42 million tonnes of inferred material within the 5.13Mt proposed open pit.

The company is also moving forward with offtake and finance discussions.

The October 2018 definitive feasibility study for Sulphur Springs outlined capital costs of $169 million for a 1.25 million tonne per annum operation.

Average annual production is expected to be 65,000 tonnes of 25% copper concentrate for 15,000t of metal, and 75,000t of 50% zinc concentrate for 35,000t of payable metal.

The project has a post-tax net present value of $310 million and internal rate of return of 39%, based on a copper price of US$6300 per tonne and zinc price of $2650/t, and an exchange rate of 72c.

Copper is currently sitting at more than $9100/t.

Venturex shares jumped more than 50% yesterday to an all-time high of A51c, but were down 11.7% to 45c.

Canaccord Genuity has a speculative buy rating and 55c price target, and a spot valuation of 75c.