Energy & Resources
Alaska's latest development stir
Mineral Resource of the Month: Silicon

Alaska’s latest development stir

Coalbed methane prospecting and development in the Matanuska-Susitna Borough (Mat-Su) near Cook Inlet, in southern Alaska, is causing quite a ruckus. Scientists have estimated that as much as 1,000 trillion cubic feet of in-place coalbed methane exists in Alaska, with an estimated 250 trillion cubic feet in the Cook Inlet region alone (at least 1.6 trillion cubic feet in Mat-Su). The natural gas would supply local residents with energy for decades, and could potentially supply energy to the entire country once infrastructure is in place for export to the lower 48.

The U.S. Geological Survey (USGS), along with the Alaska Department of Natural Resources (DNR) Division of Geological and Geophysical Surveys, has surveyed the land extensively over the past few years to determine the quantity, quality and mineability of coalbed methane. Coalbed methane is natural gas held inside underground coal seams by pressure from water above. Scientists are looking at the potential for use in rural villages, where traditional diesel fuel costs are high.

In 2002, the Alaska DNR Division of Oil and Gas Programs granted a lease to Denver-based Evergreen Resources to drill eight test wells. Alaska law grants most subsurface land rights to the state, rather than to the private landowner; therefore, the agency can grant leases to mining companies regardless of the desires of the landowner. Jack Ekstrom, Evergreen’s public affairs director, says the company, as the primary developer in the basin, tries to reach agreements with the surface landowners prior to drilling. In Colorado’s Raton Basin, where the company has more than 1,000 coalbed methane wells, they have been 99 percent effective in reaching such agreements, he says.

Debate over the Mat-Su development became heated at two public meetings the company held in early October in the region to discuss its coalbed methane plans with stakeholders. “Residents are concerned about depletion or pollution of their water wells, and the scarred landscape from the spiderweb of roads, pipelines, transmission lines and compressor stations needed to harvest the gas,” says Randy Virgin, executive director of the Alaska Center for the Environment. The water concerns stem from problems with the two primary methods of methane removal: Groundwater removal can deplete local wells, and fracturing fluids can be toxic, which may contaminate nearby wells. Some environmental groups, such as the alliance of 20 environmental organizations called the Coalbed Methane Project, say that the gas is far from a “clean fuel” — the misnomer, they say, ignores the impacts of the total fuel cycle.

“But coalbed methane has a double advantage,” says Gary Stricker, a geologist with USGS in Colorado. It burns cleaner than coal or oil, thus reducing the amount of carbon dioxide produced. And if coal mining companies can efficiently extract the methane — a greenhouse gas — before mining the coal, then the methane can be used, instead of escaping to the atmosphere. Then its capture and use could potentially reduce greenhouse gases twofold, Stricker says.

Also, new development could provide much-needed jobs and lower energy costs in the region. Mat-Su, though still largely rural, is Alaska’s fastest growing region by population, according to the Alaska Department of Labor. Some residents hope the development will bring revenue that will increase funding for schools and other public works, as has occurred in Raton. The coalbed methane could also reduce energy costs by reducing the reliance on more expensive diesel fuel, a main energy source for home heating and electrical power generation throughout much of rural Alaska.

Thus far, Evergreen has obtained subsurface lease rights to around 300,000 acres in Mat-Su. How much of the coalbed methane in the region will be economically recoverable remains unknown, Ekstrom says. But within the next four to six months, Evergreen will drill cores to obtain more geologic information and will continue experimenting with the pilot wells.

On average, 70 to 80 percent coalbed methane recovery is very good, Stricker says. The Powder River Basin in Wyoming has that recovery percentage, but it has an infrastructure in place for obtaining and moving the gas that doesn’t exist in Alaska. “You’ve got to be able to get at it,” he says.

Alaska’s remote location, harsh climate and lack of infrastructure are development challenges, Ekstrom says. Additionally, Alaska’s oil and gas regulations were developed strictly for deep gas wells and oil wells, not shallow coalbed methane wells. The deep oil and gas well regulations are designed to prevent blowouts and spills, which are not concerns for coalbed methane wells.

However, in August, Gov. Frank Murkowski signed a bill that clarified the regulations. The new law exempts shallow gas methane from many of the oil and gas well regulations, calling the regulations “ill-suited and unduly onerous when applied to shallow natural gas projects.”

“That paved the way for Evergreen,” Virgin says. “The bill totally changed the playing field,” and goes too far, he adds. The Alaska Center for the Environment is concerned about the scarring or damage of public lands, where boroughs or local ordinances may not be able to overrule state development interests. But industry officials laud the new regulations for removing unnecessary development obstacles, pointing out that coalbed methane wells are typically no deeper than 4,000 feet (traditional oil wells are usually deeper than 10,000 feet) and operate at much lower pressures than oil wells.

Though Evergreen has been monitoring its Mat-Su coalbed methane wells since 2002, Ekstrom says it can take several years for wells to be evaluated for economic viability. Having just been granted leases to 230,000 acres in September, the company will drill more exploratory wells and the test cores.

Megan Sever

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Mineral Resource of the Month: Silicon

Lisa Corathers, the Silicon Commodity Specialist for the U.S. Geological Survey, has compiled the following information about silicon, an extremely versatile mineral with many applications in the manufacture of iron and steel, aluminum alloys, chemicals, and electronic microchips.

In the industrialized world, silicon is as ubiquitous in the objects people use every day as it is in nature. The second most abundant element in Earth’s crust and more than 25 percent of the crust by weight, silicon is one of the most useful elements to humans.

Perhaps the most commonly known use of silicon is the microchip or the integrated circuit — thus its namesake, Silicon Valley. With the advent of the microchip in 1962, the high-purity grade of silicon metal (containing greater than 99.99 percent silicon) helped usher in the modern electronic age. While its importance in electronics is undeniable, this use of silicon accounts for only about 5 percent of total silicon metal consumption.

Silica (SiO2) as quartz or quartzite is used to produce silicon ferroalloys for the iron and steel industries, and silicon metal for the aluminum and chemical industries. More than half of the silicon consumed yearly in the United States is used as ferrosilicon.

Silicon carbide (SiC, the only chemical compound of carbon and silicon) is one of the hardest substances known, and is used as an industrial abrasive and as a substitute for ferrosilicon in iron-making. Steelmaking consumes some silicon metal, and the semiconductor industry refines some for use. Microsilica (silica fume) is a byproduct from furnaces that make silicon metal or ferrosilicon with a silicon content of at least 75 percent. It is used as binder and filler in cement. In the form of sand and clay, silica is a component of concrete and brick. And as sand, it is a principal ingredient of glass.

Only oxygen is more prevalent in Earth’s crust, and silica itself is not found free in nature. It occurs chiefly in oxide and silicate minerals. Sand, quartz (silica), agate, flint, jasper and opal are some of the oxide minerals in which silicon is found. Granite, hornblende, serpentine, feldspar, clay and mica are but a few of the many silicates comprised of silicon, as the name indicates.

For the past five years, ferrosilicon and silicon metal production in the United States has been from locally mined silica at the average rate of 256,000 and 158,000 metric tons per year, respectively. U.S. consumption of ferrosilicon averaged 329,000 metric tons per year, and silicon metal averaged 165,000 metric tons. Even with significant domestic resources and production, the United States annually imports silicon materials to meet demand. The reliance on imports has averaged about 42 percent for ferrosilicon and 39 percent for silicon metal. The reliance for silicon metal imports has increased steadily from 29 percent in 1999 to 55 percent in 2002; U.S. production has decreased because domestic producers have been unable to compete with imports.

World production of ferrosilicon has been approximately 4 million metric tons (gross weight) per year over the past five years. Production of silicon metal in the world, with the exclusion of China, has been about 645,000 metric tons per year. Although firm data are lacking, China’s production of silicon metal is believed to be the world’s largest. China’s annual output of silicon metal was estimated at about 300,000 metric tons in 2002.

On a silicon content basis, Western world consumption of ferrosilicon averages about 1.7 million metric tons per year, and silicon metal averages about 968,000 metric tons per year. Because of its abundance in Earth’s crust, silica reserves around the world are more than adequate to sustain silicon production levels indefinitely.

Visit the USGS minerals Web site for more on silicon.

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