Fact Check: Expert says energy industry spokesman Jon Bargas’ letter incorrect
Jon Bargas, spokesman for the Independent Petroleum Association of Mountain States, wrote in a letter to the editor Sunday that there is “no scientific evidence” supporting seismologists’ claims in my August 7 story that earthquakes, particularly those near coalbed methane fields near Trinidad, are caused by water injection during the coalbed methane drilling process.
He cited an inconclusive U.S. Geological Survey report about a 2001 earthquake swarm near Trinidad, a report I read years ago while I was covering some related 2004 and 2005 quakes in the same region for the Taos News in Taos, N.M.
Bargas claims: “The USGS report also noted that earthquake activity subsided even as injection has continued. Today, six years later, there are even more injection wells in the area, and yet we’ve seen nothing like the ‘swarm’ of earthquakes experienced in 2001. Furthermore, the implication that coal bed methane development caused a magnitude 5.3 earthquake near the Rocky Mountain Arsenal in 1967 is ludicrous, since there is no coal bed methane development in that area now nor was there in 1967.
“Coal bed methane development in Colorado is done in an environmentally responsible manner. … Stretching the truth to implicate natural gas producers in a natural disaster does a disservice not only to the thousands of hard-working Coloradans who are employed in this industry, but also to the millions of customers who rely every day on the energy produced through coal bed methane development to cook their food, heat their homes, and light their offices.”
I did not report that the Rocky Mounain Arsenal quake was caused by coalbed methane development. I reported that it was caused by liquid injection similar to that involved in coalbed methane development.
Here’s what Mesa State College seismologist Dave Wolny had to say Sunday about Bargas’ comments:
“My problem with Mr. Bargas’ comments were they were misleading, giving the appearance that there was absolutely no connection between deep well injection and seismic events. ” …
“Mr. Bargas referenced the USGS study ‘Investigation of an Earthquake Swarm near Trinidad, Colorado, August-October 2001.’ He states that it says ‘no evidence that the reported earthquakes were induced.”’ What it actually says is ‘However, although our hypocenter locations are accurate, their locations by themselves do not argue strongly for or against the induced seismicity hypothesis.’ In other words, the report was inconclusive. As of 2001, there were 10 wells that were returning water related to coal bed methane extraction to underlying rock formations as deep as 7000 feet. Eight wells were of natural flow, hydrostatic pressure alone was injecting water into the rocks. Two wells were high pressure injection types. Six years later and earthquakes continue in the area. Are they induced or natural? I don’t have the answer.
“It is a fact, proven many times, that deep well injection causes seismic events. The first evidence for that comes from the deep well injection of toxic materials at the Rocky Mountain Arsenal in the early sixties, culminating in the magnitude 5.3 event in August 1967. Deep well injection is currently being used in the Paradox Valley by the Bureau of Reclamation to remove near surface salt water and inject it in to underlying rocks. Deep well injection continues to produce events in the Paradox Valley in Western Colorado. If you are doing deep well injection, you are altering the stress on the underlying rocks and at some point, the stress will be relieved by generating an earthquake. The events are generally small, but there is no way to predict how the injection process has altered stresses on the fault system in the area, and thus, no way to predict how large the events may get. The 5.3 event at the Rocky Mountain Arsenal in 1967 proved that. As for the Paradox Valley, the Bureau of Reclamation had suggested that earthquakes related to the deep well injection process in the Paradox Valley would not exceed magnitude 3.5 (personal communication with Bureau employees), yet the area has experienced 2 earthquakes over 4.0. The majority of events remain in the range below magnitude 3.5.
“It is a fact that coal mining (as well as other types of mining) produces seismic events. If you remove the coal that has been holding up the mountain, the mountain will attempt to fill that void. Coal mining operators know that this will happen and work to mitigate the problem as best they can through engineering designs. The advent of longwall mining techniques helped in the control of roof collapses and made the miners job more safe, or at least as safe as can be reasonably expected. The collapse of the overlying rocks is expected to occur in the area behind the mining operation, thus keeping the miners safe. That is not to say that collapses can’t occur elsewhere in the mine, including older workings that have long been abandoned. The collapse of the overlying rocks, wall bursts, or floor heaves can happen. It is a part of mining, though hopefully rare in occurrence. Each of these events produces a seismic signature that can be recorded on seismometers. Usually, they are extremely small. In the case of the event at the Crandall Canyon Mine in Utah, it wasn’t small. The coal ‘bump’ associated with that collapse may turn out to be either roof collapse, wall burst, or floor heave, or a combination of any of those. I don’t have first hand knowledge of the mining technique being used at the Crandall Canyon Mine, but it is my understanding they were not long wall mining, but rather using a retreat method that involved removing supporting pillars with a remote mining machine. If that is true, as stated by numerous experts, that is a more dangerous way to mine coal (see Salt Lake Tribune, Aug. 12).
“The largest mine collapse ever recorded was at the Solvay Mine in SW Wyoming, which produced a magnitude 5.4 seismic event in February 1995. It was recorded as far away as Japan. Historically, the very largest mining related seismic events in Colorado are in the range of magnitude 3.5.”
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