Commodities trader Glencore has turned to its own internal talent for the team that will run trader and miner Glencore Xstrata after the sector's biggest takeover to date, according to a source familiar with the company.

Of the dozen or so key divisional positions in the combined company, only two will be filled by Xstrata personnel - Peter Freyberg will continue to run coal mining, and Mark Eames will take charge of the group's iron ore projects, the source said.

Despite the fact that commodities trading, Glencore's traditional strength, is estimated to account for only just over a quarter of 2014 profits for the combined group, Glencore will keep the bulk of key divisions in its own hands after a string of Xstrata departures.

The appointments - to be made public on Friday as Glencore updates investors after completing the deal on Thursday - should leave little doubt that what began as a "merger of equals" in February last year has ended - after months of often tense negotiating - as a takeover.

Glencore Xstrata's shares begin trading on Friday, but analysts and investors have already turned to the challenge Glencore will face in executing the $30 billion deal that transforms the group into a mining and trading powerhouse.

In a letter to staff on Thursday, Glencore chief executive and top shareholder Ivan Glasenberg hinted at shake-ups ahead in both staff and group assets, not least among Xstrata's pipeline of development projects that Glasenberg would like to trim down.

"We see scope to improve the efficiency of the group and optimize the combined asset portfolio and growth pipeline for the benefit of all stakeholders," said Glasenberg, who will be chief executive of the combined group.

Among the key announcements to be made public on Friday, Telis Mistakidis, Glencore's head of copper, will be appointed to run both trading and mining for the red metal within the combined group, the source said.

Copper accounted for more than half of Xstrata's profits last year and the departure of Xstrata veteran Charlie Sartain announced last month had raised questions about mining projects such as Las Bambas, the Peruvian mine Glencore will now have to sell to satisfy China's antitrust regulators.

Glencore's head of oil, Alex Beard, and the head of agricultural products, Chris Mahoney, will keep their positions in the combined group.

In coal, Glencore's Tor Peterson will remain in charge of trading operations, while Xstrata's Freyberg - the only head of a main division from that company to come over to the combined group - will take on the mining side, the source said.

In zinc, another key commodity for the combined group, Glencore's Daniel Mate will be in charge of trading, while the mining operations will be run by another Glencore executive, Chris Eskdale.

In a significant shift, Gary Nagle, the head of Glencore coal business Prodeco for more than five years, will run the combined group's ferroalloys mining operations, with Stuart Cutler in charge of trading, the source said.

Iron ore trading, a key growth area for the group, remains the preserve of Christian Wolfensberger of Glencore, while Mark Eames, who ran Xstrata's iron ore development projects, will take on mining operations, the source added.

(Reporting by Clara Ferreira-Marques; Editing by Mark Potter and Jane Barrett)