MOSCOW, Idaho – May 11, 2015 – About 75 percent of the world’s copper comes from porphyry copper deposits. A new study from the University of Idaho and the University of Michigan unearths how these economically valuable deposits are distributed around the world.
The research, published today in Nature Geosciences online, indicates that climate helps drive the erosion process that exposes porphyry copper deposits, as well as helps determine where on Earth the deposits form.
The study was conducted by Brian Yanites, an assistant professor in the UI Department of Geological Sciences, and Stephen Kesler, an emeritus professor in the Department of Earth and Environmental Sciences at Michigan. Yanites is a geomorphologist, studying the Earth’s topography. Kesler is an economic geologist, studying the formation of deposits that can be mined for raw materials.
“This is the first time that we’ve found a connection between geomorphology and economic geology,” Yanites says. “It’s exciting to think that erosion and the building of our mountain landscapes influences where society gets its resources from, and it’s another line of evidence of the importance of climate in the shape of the landscape.”
Porphyry copper deposits initially form beneath volcanoes, on average 2 kilometers below the surface. Over the course of millions or tens of millions of years, erosion exposes them.
Yanites and Kesler examined data on the age, depth and number of exposed porphyry copper deposits in regions around the world. When they compared these data to the regions’ climates, they noticed a pattern: The youngest deposits are found in areas of high rainfall, such as the tropics, indicating rapid erosion. Deposits are older in dry areas, indicating low rates of erosion.
They then counted the number of deposits in the different regions and found something striking: Where erosion is rapid, there were relatively few deposits, but locations with low erosion rates contain a high density of deposits. Such regions include the Atacama Desert in the Andes Mountains and the American Southwest — both places where porphyry copper mining is important to the economy.
The researchers developed a simple model to explain the relationship between erosion rate and the number of deposits in a region. Yanites compared it to a game on the TV show “American Gladiators,” where competitors had to run past tennis-ball launching cannons to reach their goal.
“The faster the competitors run, the lower the chance that they will get hit because they spend less time in the ‘danger zone,’” Yanites says. “Similarly, rock layers that spend less time in the porphyry production zone — due to rapidly eroding landscapes above — have less of a chance of getting injected with one of these valuable deposits.”
USDA Announces Funding for Smart Grid and 1,000 miles of line on 80th Anniversary of Rural Electrification
WASHINGTON, May 11, 2015 - Agriculture Secretary Tom Vilsack today announced that USDA is providing more than $100 million in loans to build or improve 1,000 miles of electric transmission and distribution lines for rural electric cooperative utilities in four states.
"We commend rural electric cooperative utilities nationwide as we celebrate the 80th anniversary of the creation of the Rural Electrification Administration," Vilsack said. "Investments we make to provide rural communities with electricity are critical to our nation's economy. Our commitment to rural electricity has powered our growing agricultural exports, a burgeoning bio-economy and the quality of life for rural Americans."
The four loans include $9 million for smart grid improvements. In Indiana, Johnson County Rural Electric Membership Corporation will use a $14 million loan to build or improve 345 miles of line and make other system improvements, including $4.8 million for smart grid projects.
Thumb Electric Cooperative of Michigan will use a $25 million loan to build or improve 93 miles of line and make other system improvements, including a $2.7 million smart grid investment.
In North Dakota, Slope Electric Cooperative, Inc. has been selected to receive a $12.5 million loan to build or improve 66 miles of line and make other system improvements, including $432,000 for smart grid technologies.
South Carolina's Santee Electric Cooperative, Inc. is receiving $54.8 million to build or improve 605 miles of line for residential and business customers. The loan also includes $3 million for storm damage restoration.
USDA's Rural Utilities Service, which funds utility infrastructure in rural areas, is the successor to the Rural Electrification Administration (REA), which was created by then-President Franklin Delano Roosevelt on May 11, 1935. Congress approved statutory authority for the REA on May 20, 1936. The agency became part of USDA in 1939.
USDA is providing $106.3 million in electric system infrastructure loans in today's announcement. The Rural Utilities Service awarded $2.4 billion in electric loans in 2014 to help 4.6 million rural residents receive improved electric service. Since 2009, USDA has invested almost $31 billion in rural electric systems, including more than $1 billion in renewable energy projects.
"While the country suffered in the Great Depression, President Roosevelt led a national commitment to bringing power to rural America," Vilsack added. "That commitment helped make America the breadbasket of the world and most productive country in history. USDA's Rural Utilities Service is honoring that commitment by taking on today's challenges, including smart grid technology and advanced telecommunications and broadband access."
President Obama's plan for rural America has brought about historic investment and resulted in stronger rural communities. Under the President's leadership, these investments in housing, community facilities, businesses and infrastructure have empowered rural America to continue leading the way - strengthening America's economy, small towns and rural communities.
USDA's investments in rural communities support the rural way of life that stands as the backbone of our American values. President Obama and Agriculture Secretary Vilsack are committed to a smarter use of Federal resources to foster sustainable economic prosperity and ensure the government is a strong partner for businesses, entrepreneurs and working families in rural communities.