Markham Main and the rest represent the vanguard of coal privatisation - pits leased and licensed from British Coal on an individual basis. Privatisation of the rest is expected to be completed by the end of 1994.
The confidence of the new owners raises the question: why do they believe they can make profits if British Coal could not?
But for the public outcry over the 31 pits announced for closure in October 1992, these would never have been licensed. Abandonment by British Coal would have meant that they were lost for ever, together with the jobs they provide. Allowing them to be licensed individually appeased public opinion.
Malcolm Edwards, former commercial director of British Coal and now head of Coal Investments, the company operating four former British Coal deep mines, believes there is no secret formula to make the pits economic.
While British Coal remains heavily dependent on the power station market, Mr Edwards' pits - Markham Main, Coventry, Trentham and Silverdale - will produce high quality coal enabling them to succeed in the industrial and domestic market without necessarily selling to the generators. 'It requires radical rethinking. You have to select the right colliery to meet the needs of the market. It has caused a lot of sleepless nights, though.'
The 'radical rethink' has had wide-ranging implications - for production techniques, working practices and industrial relations. Mr Edwards is bringing effective mining practices from abroad. These include the use of continuous mining machines that are remotely operated and work entirely within the seam section, producing low-ash coal.
Industrial relations have also changed. Markham Main, under British Coal, had a reputation as one of the most militant pits in the country. Asked about the status of the National Union of Mineworkers at Markham now, the response from a welder at the pit is astonishing: 'To tell you the truth, the union is not something that's ever discussed.'
The company policy on unions is clear. Miners may join any union they like, and Mr Edwards says he would advise them to do so. If the men decide to elect a representative, Mr Edwards will negotiate with him. Pit-based representation for the NUM may still be a possibility, whereas the inclusion of the national and area NUM in negotiations has probably gone for ever. 'A lot of the history of coal has gone - all that is dead,' Mr Edwards says.
On at least one issue there is agreement between Mr Edwards and the NUM leadership. British Coal has been trying to introduce 'flexible working' at its remaining mines. One aspect of this is lengthening shift times, to which the NUM is vehemently opposed.
Mr Edwards shares that view. 'Twelve-hour shifts are a bloody disgrace. Very long shift working doesn't pay off. We're on eight- hour shifts, the men are rostered, five days over six, to keep the mine working and the teams together.'
Malc Hart, shift manager at Markham Main, believes the atmosphere at the pit has changed completely since Coal Investments took over. 'We have a feeling now of all working together. It is not 'us' and 'them' any more.' This exemplifies the participatory business culture Mr Edwards is trying to instil. He has set up a share ownership scheme he believes will help the management to run the four pits effectively. Every worker will have a share in the business.
Arthur Scargill believes such schemes blunt the potential militancy of workers, who are blinded into thinking that, on the basis of what is often a small shareholding, they are somehow owners rather than workers.
Despite the views of the national leadership, the South Wales area of the NUM is preparing a bid to take over Tower colliery, the last British Coal mine in South Wales.
The NUM national leadership has consistently opposed buyouts of pits - even worker buyouts - as being a back-door route to privatisation that might be more easily sold to a workforce desperate to retain jobs. It argues that working conditions for miners will worsen and workers investing their own money are likely to lose it.
Nevertheless, in recent times the alternative to these buyouts has been closure. The Yorkshire area of the NUM, in its heyday of 1975, was exploring leasing a coking plant near Barnsley. The plant, owned by a private company next to British Coal's Barrow colliery, was facing closure and the proposal was an attempt to save it. The prospective lease never came to fruition, but the union believed it could make money from the plant as well as saving jobs. Arthur Scargill led the negotiations.