BUILDING work on Bolton's new £1 million kidney dialysis unit was delayed -- after mineshafts were discovered underneath the site.

Builders have been forced to fill in the underground tunnels which were used by miners over 100 years ago.

The extra work and two week delay added an extra £75,000 to the cost of the project.

The 18-bed unit is being built on the edge of the Royal Bolton Hospital's Minerva Road site.

Health chiefs have revealed that the extent of the elaborate network of old mining tunnels directly underneath the plot of land earmarked for the new unit was more extensive than the builders had expected.

They are now hoping they will be reimbursed the additional cash outlay by the government-controlled Renal Specialist Commission which has paid for the massive development. The commission will eventually run the unit.

Work to fill in the tunnels was carried out immediately they were discovered and only resulted in a two week delay.

Parts of Farnworth, Over Hulton, Westhoughton and Leigh are known to be riddled with small mineshafts, some stretching for many miles.

Despite the setback, the kidney unit is still set to open in spring next year.

Once built, the facility will become the only purpose built dialysis unit in the country. The construction of the long-awaited centre, due to have been started earlier this year, has already been delayed once because Royal Bolton Hospital bosses asked for more money from the Government to build a bigger unit. Local patients currently receive treatment at the Manchester Royal Infirmary, Salford's Hope Hospital and Wythenshawe Hospital and face long travelling times.

Chief Executive of the hospital trust, Mr John Brunt , said that the discovery of the mineshafts had been unexpected.

"I think the builders have underpinned half of Farnworth", he joked to hospital trust board members. But the finance director of the hospital, Mrs Beverly Peacock, was concerned that the extra money would put pressure on the cash-strapped hospital funds. He added: "Although we will be providing services at the unit, it will not be us that runs it."

Joint projects of this kind should not adversely effect the capital of the host site."