Findings of a Sandia research team were a key source of a recently released report by the US Mine Safety and Health Administration (MSHA) indicating that lightning was the likely cause of the explosion in the Sago Mine on Jan. 2, 2006. The disaster killed 12 miners.
As part of its official investigation, MSHA contracted with Sandia to study if energy from a lightning strike could travel underground to potentially ignite an explosive mixture of methane gas trapped in a sealed section of the Sago Mine. Three lightning strikes were recorded by national detection networks, along with eyewitness accounts of other strikes nearby the mine, just prior to the explosion. The bolts struck nearly simultaneously with the explosion that was registered by seismographs and carbon monoxide monitors at the mine.
Operations at the mine were officially idled in late March by mine owner International Coal Group, Inc. A small crew remains employed at Sago to maintain the mine infrastructure.
In early November a Sandia team took its test monitoring equipment across the country to the Sago Mine, located near Buckhannon, W.Va. They spent 10 days analyzing the likelihood that electric current produced by a lightning strike could transmit effects deep into the coal mine.
Their findings became part of the final MSHA accident investigation report delivered to Congress on May 9.
“We never expected to discover a smoking gun,” says Larry Schneider, senior manager of Sandia’s Pulsed Power Technology Dept. 1650. “However, we pursued and characterized a coupling mechanism that the team of accident investigators hadn’t previously considered — that current from a surface lightning strike can generate electromagnetic fields that can readily propagate through the earth, as opposed to current being driven into conductors entering the mine such as metal rails or power lines. Our findings had profound implications.”
The Sandians, including project lead Matt Higgins, Dawna Charley, and Leonard Martinez (all 1653) with support from Marv Morris, a contracted consultant and former Sandian, conducted the experiments at the mine. Matt, Dawna, and Leonard worked at the site for 10 days last November.
MSHA knew of Sandia’s lightning work
The Mine Safety and Health Administration — aware of Sandia’s decades of work studying lightning, particularly how it might impact critical nuclear weapons facilities at the DOE Pantex Plant located outside Amarillo and underground facilities at the Nevada Test Site — asked the team to conduct the experiments and analysis.
“Accident investigators had been suspicious all along that lightning was the cause of the explosion, but there had been no definite proof one way or the other,” says Michele Caldwell, manager of Electromagnetic Qualification and Engineering Dept. 1653.
Twenty-nine miners were underground at Sago when the explosion occurred. Thirteen were in close proximity to the blast. As was later learned, the force of the explosion killed one miner outright, and 12 others retreated behind a curtain at the working face of the mine in an attempt to barricade themselves against the smoke and carbon monoxide. They awaited rescue there, which would come too late for all but one of them.
With lightning as a potential cause for the Sago Mine explosion, the Sandia team investigated two modes of transmitting lightning energy deep into the coal mine, Michele says.
The first mode was direct attachment onto metallic penetrations — such as conveyers used to extract the coal, rails used for transporting people and equipment — and power and communication lines from the entrance to deep inside the mine. The second mode investigated energy propagating through the earth’s surface from the point of a surface lightning strike or overhead arc channel.
“We needed to be able to make measurements without waiting for or triggering a true lightning strike in the vicinity, so we provided our own drive signal,” Michele says. “To prevent interference with mine operations or introduction of a safety hazard, we injected a small, continuous signal over a range of frequencies present in a lightning strike as a drive source.”
For the metallic penetrations, the drive signal was applied at the entrance to the mine and signals were measured with current and voltage probes at various points in the mine, as far as two miles in. The drive signal was transmitted by fiber optics to the entrance of the mine as the instrumentation was carried inside the mine to make measurements. The goal was to see how much the signals decreased as a function of the distance from the entrance of the mine.
For measuring propagation of lightning energy from the surface of the earth to the mine cavern 300 feet below, the drive signal was applied to a long wire stretched on the surface. Directly below, inside the mine, an antenna was set up to pick up the transmitted signals. Multiple antenna measurements were made, covering a cross pattern in the mine of about 80 meters by 80 meters. The measurements were compared to analytical models simulating lightning field propagation through the earth.
The data were used to develop transfer functions, a way of understanding how much energy penetrated into the mine based on a surface lightning event. These results were combined with a theoretical lightning strike waveform to determine if voltages get high enough inside the mine to be of concern.
The study concluded that it was highly unlikely that lightning initiated the explosion by traveling along conductors through the mine and into the sealed area. However, electromagnetic energy from a significant lightning event close to the sealed area could travel through the ground at Sago to create high voltage in the sealed area, subsequently creating a spark, a known ignition source of flammable methane mixtures.
A brief, but powerful look
“The results of field measurements and analytical modeling were clear; lightning can propagate significant electrical energy into mine systems under the right conditions,” says Larry. “The team’s work at Sago was only a brief, but powerful look into this effect. We need to better understand this phenomenon in the variety of scenarios seen in the US mining system. I can readily envision this leading to additional, reasonable preventative measures to reduce the probability of such a catastrophic event in the future. This is an important message.”
Larry says he is grateful for Sandia’s relationship with MSHA.
“I need to compliment MSHA for their engagement of Sandia. The techniques we used in our work for them were not generally understood outside the nuclear weapons community. It took technical insight and courage on their part to embrace this work. We’re very pleased that Sandia played an important role in this investigation.”
By Patti Koning
California is leading the nation when it comes to energy and environmental policy. Last year Gov. Schwarzenegger put California on the world stage when he committed the state to reducing global warming emissions back to 1990 levels by 2020.
In an effort to stay abreast of developments in the rapidly advancing field of clean energy and related government policy, Sandia’s ERN/SMU CA Energy Liaison Office and its Division 8000 Business Development Office hosted a visit by Dan Adler of the California Clean Energy Fund (CalCEF). Adler is the Director of Technology and Policy Development at CalCEF.
According to Carrie Burchard (8529), Sandia’s work in “Cleantech” is generally much closer to commercialization than some of the other areas of research at the lab. Engaging with CalCEF enables the Business Development Office to look at alternative funding possibilities and aligning research with what is happening in the state.
“We often look 10-20 years out, but in this arena we need to be looking ahead five years,” she says. “Biofuel, including cellulosic ethanol and biodiesel from algae, is just one area where we are reapplying the capabilities we developed in our homeland security work to energy issues.”
CalCEF is a $30 million nonprofit investment fund created to spur investment in California’s clean energy economy. The fund was formed in 2004 from the PG&E bankruptcy settlement negotiated by the California Public Utilities Commission (CPUC).
This is where the interests of CalCEF and Sandia intersect. The companies funded by CalCEF could be potential business partners with Sandia. Burchard says it is also an opportunity for Sandia to strengthen its relationships with California government.
Adler thinks there are great opportunities for CalCEF and Sandia to develop a common platform for technology commercialization, a regular forum for interaction with the venture capital community, and a means of mutually reinforcing state policy efforts via insights into emerging energy research.
The Global Warming Solutions Act that took effect on January 1, 2007 will have a big impact on any company doing business in California. These companies will be actively looking for solutions to reduce their greenhouse gas footprint.
Ron Stoltz (8302), head of the California Energy Liaison Office, envisions the relationship between Sandia and CalCEF as a two-way information exchange. Sandia can advise CalCEF on promising technologies, while CalCEF can provide insight into trends in venture capital investing in clean energy. Ron and Adler already have future meetings planned to further this partnership.
“The overall intent is for us both to be ahead of the crowd in the future of clean technology innovation and investing,” Ron says. “I don’t expect CalCEF to directly fund Sandia, but they can make us aware of promising companies through which we can commercialize our inventions.”
Adler noted that “I’m impressed by the breadth of clean energy work undertaken by scientists at Sandia, and by the entrepreneurial spirit and outward-orientation of the members of the management team I had a chance to meet.”
CalCEF recently gave a $1 million grant towards the establishment of an Energy Efficiency Center (EEC) at the University of California, Davis. The goal of the EEC is to accelerate energy efficiency innovation and to stimulate the transfer of the technology into the marketplace.
CalCEF operates independently of both PG&E and the state of California. The fund is a limited partner in three venture capital funds.
During Adler’s visit, Ron led a spirited panel discussion in which he played the role of Vinod Khosla, a Silicon Valley venture capital investor. Khosla, who co-founded Sun Microsystems, recently has been pursuing investment in bio refineries, synthetic biology, and fuel and solar cells.
On the panel were Blake Simmons (8755), representing energy systems; Lennie Klebanoff ( 8755), representing hydrogen; Art Pontau (8750), representing materials and energy sciences; Margie Tatro (6200), representing fuel, water, and alternative energy; and Masood Hadi (8321), representing biosystems research.
The panel debated and discussed concentrated solar versus photovoltaics, the merits of electricity peak shaving and load shifting, hydrogen, nuclear power, and how the rising popularity of plug-in hybrid vehicles could impact the energy market.
Lennie, Director of the DOE Metal Hydrides Center of Excellence, was quick to defend the merits of hydrogen after Vinod (aka Ron) suggested that “hydrogen makes no sense to me.”
“You can’t sequester the mobile source of carbon emissions—exhaust from your car’s tailpipe,” Lennie says. “That’s why it is essential we look at hydrogen. Hydrogen is a storage medium, not a fuel.”
The purpose of the discussion was to look at alternative points of view about energy and to challenge assumptions. While the panel participants all work directly in clean energy technology, Ron says the focus was “less on what we are doing and more on what we are thinking.”
After the panel discussion, Adler toured the hydrogen storage and hydrogen engines combustion labs and learned about the applications of fiber lasers to energy problems from Dahv Kliner.
“Sandia’s expertise in combustion research should be of great use in the development of next-generation biofuels, which is a major emphasis in the policy and financial arenas,” Adler says.
Adler’s visit, and especially the panel, accomplished another goal of Burchard’s.
“We need to spend more time talking about difficult, hot issues,” she says. “It gets the intellectual juice flowing.” -- Patti Koning
By Patti Koning
Sandia/California recently was awarded a prestigious DOE Pollution Prevention (P2) Star Award for the implementation of the site’s Environmental Management System (EMS).
“This is the highest pollution prevention award given out by DOE,” says Janet Harris (8516). “More importantly, this award recognizes the hard work of our entire site in implementing the EMS quickly and effectively.”
Titled “Unique Approaches and Techniques Resulting in Rapid and Effective EMS Implementation at SNL/CA,” the project first received an NNSA Environmental Stewardship Award last December. Those winners were then advanced to the DOE P2 Star Awards competition, which includes the entire DOE complex.
The team behind this effort received a Gold President’s Quality Award (PQA) for their work in 2006.
Sandia/New Mexico also received a DOE P2 Star Award for “HERMES III Waste Minimization Practices.”
Sandia/California implemented its EMS program in just 14 months, a process that took most other DOE facilities several years to complete. In 2003 DOE set a requirement for all of its facilities to have an environmental management system in place by December 2005.
Initially, Sandia/New Mexico led the EMS effort for all Labs sites. During the process it became clear the California site needed a separate EMS program because of the different environmental aspects of the two sites, especially in geography, local environmental laws, and the nature of the work conducted. Radioactive waste and heavy noise, for example, have a much lower risk ranking for California than for New Mexico.
In ranking the risk of environmental aspects, Sandia/California examined conditions under normal and off-normal operations to account for existing controls and compliance programs. Consideration for off-normal events allowed the inclusion of emergency aspects such as earthquake and fire as environmental aspects in the program.
A 2003 study by the US Geological Society concluded there is a 62 percent probability of at least one magnitude 6.7 or greater quake striking the San Francisco Bay Area region before 2032.
In October 2004, the site established a core team consisting of Mark Brynildson, Deanna Dicker, Laurie Farren, Leslee Gardizi, Janet Harris, Robert Holland, Barbara Larsen, and Gary Shamber, all of Environmental Management Dept. 8516. The initial goal was to exceed the DOE requirements and establish an EMS that could achieve ISO 14001:2004 certification by the end of FY2007.
The core team started with a strong project management approach. They performed a detailed gap analysis against both DOE and ISO requirements. The gap analysis looked at which aspects of the DOE order the site was already meeting, and what was necessary to meet the remaining aspects.
“The results of the gap analysis were very encouraging,” says Barbara Larsen (8516), Environmental Planning & Ecology Program lead. “We found we weren’t missing much. The big pieces, such as targeted environmental programs and implementation of compliance requirements, were already in place. We needed to work on the supplemental activities such as documentation, communication, and training.”
In July 2005, the California site plan was audited by ES&H, Quality, and Safeguards & Security Dept. 12870. The auditors completed only a desk audit and interviewed core team members to verify that the elements of the EMS program met DOE requirements.
The EMS program has 19 aspects, each with its own broad objective to minimize environmental impact. Specific targets, including chemical inventory reduction, large-scale recycling, minimizing refueling on Spare the Air days, and green purchasing, support achievement in meeting the objectives.
“Our environmental aspects impact everyone in some way. Everyone made small changes for a big net effect,” says Janet. “In shipping and receiving, wood pallets are now recycled. Maintenance changes routine equipment fueling on Spare the Air days. OMAs seek out green purchasing whenever possible.”
The EMS has resulted in substantial progress in many environmental program areas. The hazardous material inventory was decreased by 15 percent in FY05 and an additional 12 percent in FY06, exceeding the goals set for both years.
Electrical energy use has declined significantly, from 38,483 megawatt hours (MWHs) in FY04 to 35,974 MWHs in FY06, a reduction of nearly 10 percent. By the end of FY2006, the site was recycling 3,836 pounds of toner cartridges, 1,367 pounds of aluminum beverage containers, 882 pounds of glass beverage containers, and 661 pounds of plastic beverage containers.
Barbara says a key ingredient to the success of the EMS was the commitment from site management, notably then-Div. 8000 VP Mim John.
“Having Mim’s firm commitment really helped in rolling out the EMS,” she says. “And Paul Hommert continues to provide a high level of support, leading the site in embracing this process. Everyone here has really put their arms around the EMS and taken ownership.”
Another key factor was the Interdisciplinary Team (IDT), which won a President’s Quality Award in 1999. The IDT consists of representatives from each environmental, safety and health (ES&H) subject area, facilities, and security. The IDT reviews all new or modified site activities and projects for their potential environmental impacts, and provides for incorporation of all environmental requirements.
The auditors approved Sandia/California’s EMS program with noteworthy recognition for going above and beyond the requirements. Division 8000 was the first in all of Sandia to self-declare that it had met the DOE requirement.
With the EMS plan in place, the core team pushed forward and achieved ISO 14001:2004 certification in September 2006, a year ahead of schedule. Division 8000 is the first organization at Sandia to receive this certification and is being viewed as a pilot for Sandia/New Mexico, which is aiming to receive certification by the end of FY08. -- Patti Koning