CONSOL Energy has begun sealing the Buchanan mine near Mavisdale, Virginia, USA, in compliance with a recent safety agency requirement that the mine be sealed for a period of time as a final step prior to re-entry in order to ensure that the mine atmosphere is inert and incapable of supporting combustion. Based on assumptions regarding the time necessary for the mine atmosphere to become inert as well as a subsequent waiting period, company engineers project that conditions will allow re-entry in early January, 2008.
Although current sampling of the underground environment at the Buchanan mine indicates safe and stable conditions, safety agencies have required that the company seal all mine openings — the agencies’ traditional method of creating an inert environment underground — prior to approval of re-entry into the mine.
The company has established more than 100 monitoring stations, allowing the mine atmosphere to be thoroughly sampled. In addition, the company has drilled approximately 50 boreholes into the mine that allow water or inert gases to be pumped into areas where the possibility of combustion might exist. A small mined-out area near the current location of mining has been the focus of intensive monitoring efforts. Water and inert gases were injected into the area when elevated levels of carbon monoxide were detected. It is believed that these actions have eliminated any possible combustion.
Production at the mine was suspended on July 9, 2007, after several roof falls in previously mined areas damaged some of the ventilation controls inside the mine, requiring a general evacuation of the mine.