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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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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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