The re-election of Frans Baleni as the general secretary of the National Union of Mineworkers (NUM) has far-reaching implications for the Congress of South African Trade Unions (Cosatu), particularly for its own secretary, Zwelinzima Vavi.

Mr Baleni’s views are aligned more to those of Cosatu president Sdumo Dlamini, and as the general secretary leading the largest delegation to Cosatu’s national congress in September, Mr Dlamini’s more diplomatic approach to issues such as leadership and alliance relations is likely to hold sway.

Mr Baleni’s ascendancy means the group close to Mr Dlamini has more authority to neutralise Mr Vavi, who has been critical of President Jacob Zuma’s government.

While Mr Vavi’s voice in the federation will not shrink, those in the Zuma camp within the unions have been boosted by the re-election.

Mr Baleni is close to African National Congress (ANC) secretary-general Gwede Mantashe and South African Communist Party (SACP) general secretary Blade Nzimande, key players in Mr Zuma’s re-election bid. Mr Baleni replaced Mr Mantashe as general secretary of the NUM.

Among Mr Vavi’s key supporters is Irvin Jim, the vocal general secretary of the National Union of Metal Workers of SA (Numsa). Unlike the NUM, Numsa is more militant in its approach and closer to Mr Vavi.

With his re-election all sown up, Mr Baleni is now poised to tackle Numsa over membership, sources say. The two unions often clash about representing workers in the industries in which they operate.

It is a numbers game and a battle for control of Cosatu. The NUM congress resolved to compel Cosatu to aid it in having about 7000 members - employed at Eskom and organised by Numsa - returned to the mining union, from Numsa. Mr Baleni said Numsa had even begun recruiting workers from the mining and construction sectors - which is solid NUM terrain.

Delegates at the NUM’s four-day congress told of regional leaders who had lost out in elections being spotted recruiting for Numsa.

"Not only is Numsa not handing over membership but starting to recruit in pure mining and also in construction. That’s hardening attitudes," said Mr Baleni.

Delegates mandated the NUM’s national executive committee to deal with the matter. One of the options it would explore is forcing Cosatu to intervene by threatening to withhold the NUM’s subscription fees. Unions pay a monthly subscription to be affiliated to Cosatu, and that of the NUM is R800 000. It is one of the wealthiest unions in the country.

Mr Baleni said its current total savings stood at R220-m and it had amassed R134,4-m in reserves over the past three years.

The reserves would be used to "cushion" the union in case of a dramatic loss of membership, he said.

However, Mr Baleni said, the national executive committee would have to weigh its options carefully, as withholding subscription fees may have constitutional implications for the union.

Mr Vavi, as organisational head, is likely to be tasked with ironing out the matter. This would place him in a tight corner, given his proximity to Mr Jim.

Numsa and the NUM historically have been at odds with one another over their posture towards politics, with Numsa often labelled as a "workerist" union - a term for a narrowly focused union - which is more removed from political parties in the ruling alliance.

The NUM is historically close to the parties, with its top leadership - president Senzeni Zokwana and Mr Baleni - on the SACP’s central committee.

The NUM has provided a powerful platform to catapult the political careers of its general secretaries - former ANC secretary-general Cyril Ramaphosa, current secretary-general Gwede Mantashe, and ANC deputy president Kgalema Motlanthe all held the position at one time or another.

"If you can run the NUM and lead this complex organisation, you are tested in many forms, you have to be a shrewd administrator, you have to be a financial accountant, you have to be a legal person, you have to be a negotiator, you have to be a politician at the same time, so it’s a platform that makes you rounded and if you can’t learn in this office, you will never learn," Mr Baleni said on the sidelines of the congress last week.

A loss for Mr Baleni, and a victory for his challenger Oupa Komane would have been ideal for Mr Vavi, says a union source.

It would have given him control of the biggest union, allowing him to direct Cosatu in his own way, especially as they head towards the ANC’s leadership conference in December.