Dr Wojtek Wodzicki stepped down from the top jobs at Josemaria but will remain a director and will focus on his role as president of NGEx Minerals.
Josemaria Resources formed mid-year as a rebadged NGEx Resources, which spun out exploration projects including Los Helados in Chile into the newly-created NGEx Minerals.
"We are putting together a management team and board with the capability to develop Josemaria and are pleased to welcome Adam Lundin to head up the company," chairman Ashley Heppenstall said.
"The focus over the forthcoming months at Josemaria will be to replicate the development success of Lundin Gold."
The company is aiming to deliver a feasibility study for the project, 10km from the Chilean border, in the first half of 2020.
A prefeasibility study in late 2018 had outlined initial capex of US$2.76 billion with an after-tax NPV (8% discount) of $2 billion and IRR of 18.7%.
The 20-year mine was slated to produce an average 125,000 tonnes of copper, 230,000 ounces of gold and 790,000oz of silver annually.
Lundin family trusts hold 36% of Josemaria Resources.
Its shares closed up 7.2% or C5c yesterday to 74c, up from a 52-week low of 63c reached earlier this month.
It is capitalised about $185 million (US$140 million).