Climate considerations could encourage mine companies to drain and use methane from their coal beds and effectively enhance worker safety -- a practice some experts say could win favor in the wake of the deadly disaster this week at a West Virginia mine.
The U.N. Economic Commission for Europe (UNECE), in a set of new guidelines released yesterday, said draining methane can allow coal mining companies to both reduce explosive hazards and lower emissions of a potent greenhouse gas.
Raymond Pilcher, chairman of UNECE's Task Force on the Economic Benefits of Improving Mine Safety Through Extraction and Use of Coal Mine Methane, said the report was particularly geared toward countries like China and India, where coal mining is growing and accidents are far more common.
"That's where we had targeted the audience for this. It's clear to me now that we should probably send one to Mr. Blankenship, as well," Pilcher said, referring to Massey Energy Co. CEO Don Blankenship, whose company owns the Upper Big Branch South Mine, which exploded Monday.
At least 25 miners were killed in the mine blast, the country's worst since 1984. Four other miners were still missing yesterday. Massey, meanwhile, is under intense scrutiny for hundreds of recent safety violations at the mine, including some to its mine ventilation plan. While the cause of the explosion is still undetermined, safety officials are focusing on whether methane leaked from a sealed-off area of the mine and accumulated to combustible levels, according to news reports.
No one yesterday suggested that a mine methane drainage system could have avoided Monday's explosion. But Pilcher also is not the first to want to talk to Blankenship about coalbed methane drainage and recovery at the mine, mostly for climate concerns.
EPA named W.Va. mine one of nation's 'gassiest' in 2005 report
Today, mainly to protect miners, boreholes that draw off methane from in and around a coal seam are used at some gassy mines, either before or after mining operations, according to the UNECE report. These drainage wells typically reduce the methane that enters the mine shaft or adjacent areas. This lowers the workload for the mine ventilation system and the risk it might be overwhelmed.
But drainage is not required directly by any U.S. safety regulations, especially because it is not always technically possible. Less than half of the 50 gassiest coal mines have degasification systems in place, according to U.S. EPA.
In the future, climate change -- and especially a potential price on carbon -- could make the expensive systems more attractive, Pilcher and others said. That's because direct drainage is generally a prerequisite for economically recovering and using methane for electricity, heat or natural gas instead of ventilating dilute streams out of the shaft and back to the atmosphere.
A 2005 report from EPA's long-running coalbed methane outreach program actually profiled the Upper Big Branch South Mine as one of the nation's 50 "gassiest" active underground coal mines that is a good potential candidate to utilize its methane and reduce its greenhouse gas emissions.
In 2003, according to the report, Upper Big Branch South vented more than 3 million cubic feet of methane a day. That's a large amount, experts say. But it did not drain any methane from the coal seam before it entered mining areas and required ventilation to the atmosphere. The report did not evaluate the feasibility of such a system.
Today, whether a gassy mine drains methane is mainly linked to safety considerations, mine economics and engineering feasibility, Pilcher said.
Regulators require that the mine operator keep methane levels below allowed levels or temporarily shut down operations if it cannot. But it is entirely up to the mine owner to decide whether it needs a methane drainage system to meet these requirements.
Currently, only 24 U.S. underground coal mines use degasification systems, according to EPA, so half the gassy mines that EPA says have the potential to use methane do not.
'Something that the company should look at very seriously'
Typically, the drainage boreholes, drilled from either inside the mine or the surface, can be expensive to operate and install, according to the UNECE report. The amount of methane a mined coal seam vents varies by geologic formation and depth, so some mines are gassier than others. Globally, mining companies are producing more methane as they seek to extract more coal from deeper depths, the report says.
But drainage systems can also make mines more productive and profitable by reducing temporary safety shutdowns, said Pilcher, who is president of a coal mine methane consulting company in Colorado.
Noting the Massey explosion, he said companies may weigh safety and economic factors differently. If a company does not make safety the highest priority, it might be more willing to accept occasional shutdowns or violations if installing a drainage system is more expensive. "Depending on the mine owner, it is probably driven more by one than another," he said.
In West Virginia, seven active underground mines -- the most in any state in the country -- degasify. None are owned by Massey, according to a 2008 EPA report.
Notably, this later report included another methane recovery candidate list of the 50 gassiest mines. This time, the Upper Big Branch South Mine was not on the list because it vented less methane gas in 2006 compared to 2003. By that time, its coal output had also fallen to less than a third of its 2003 production, according to U.S. Mine Safety and Health Administration records.
Pilcher said that the drop in coal production probably was why the mine was less gassy, but also wondered if the opposite could be a factor: that methane issues at the mine could potentially have slowed mine productivity. Massey did not respond to a call for comment.
Without knowing the specific circumstances at the Massey mine, Pilcher could not say whether a methane drainage system would have helped reduce explosive hazards from methane or even been feasible to install.
But, he said, "it should at least certainly be something that the company should look at very seriously, or should have looked at very seriously. From my perspective, really one of the questions that should be asked is: Could a drainage program have resulted in safer conditions?"
Cap-and-trade arguments for methane use
Coal mines today account for about 10 percent of U.S. man-made methane emissions. Methane has more than 20 times the climate-warming potency of carbon dioxide.
Today, there is not always a good financial incentive for mine owners, which of course are in the coal business, to use methane or even simply flare it off. Even for mines that have drainage systems, there are additional expenses to use methane, such as collecting or cleaning the gas, the UNECE report notes.
Fourteen of the 23 underground mines that operated drainage systems as of 2006 sold the gas or used it to generate power or heat on-site, according to EPA. In total, the U.S. industry recovered and used about 86 percent of all drained coal mine methane that year.
Historically, it is high natural gas prices that have encouraged mine methane recovery, either in advance of or after mining, said Texas petroleum engineering professor Walter Ayers. And in the past two decades, a tax incentive has actually encouraged plenty of natural gas drainage from coal beds -- but many of the wells are in seams that haven't been or may never be mined.
Pilcher said some similar incentive could encourage mines that don't already operate drainage systems to think about using their methane. With today's lower natural gas prices, the economics aren't so grand today, said Pilcher.
"With better incentives, especially cap and trade, clearly, projects could get a boost," he said.