A committee of leading physicists today advocated the renovation of the
125-year-old Homestake Gold Mine in the Black Hills of South Dakota as a
unique underground science laboratory.
The National Underground Science Laboratory Committee, appointed by the
Institute for Nuclear Theory at the University of Washington, met last
weekend in Berkeley, Calif., and determined that Homestake provides an
unparalleled opportunity for the United States to explore frontiers in a
wide range of sciences that require absolutely quiet environments.
John Bahcall of the Institute for Advanced Studies in Princeton, N.J., who
chairs the committee, noted that leading American scientists currently must
work in deep underground laboratories in other countries.
"For example, the technique for measuring the mass of elementary particles
known as neutrinos by observing a large tank of water was developed by
American scientists in a mine near Cleveland. But when the most significant
experiment to date was finally done, American scientists needed to work with
others in a mine in Japan," Bahcall said. Determining neutrino mass is key
to understanding fundamental forces in the universe and the nature of the
Big Bang.
"Homestake will become a gold mine for science discoveries about physics,
astronomy, biology and geology," Bahcall said.
"There is a very wide range of science that absolutely requires a deep
underground location," said Kevin Lesko of the University of California's
Lawrence Berkeley National Laboratory, the committee's co-chairman. Lesko
said other topics for a national underground laboratory include the nature
of the sun's interior, better understanding of supernovae, searches for dark
matter, behavior and evolution of life in exotic environments,
characteristics and stability of geologic structures, evaluation of
groundwater resources, monitoring of nuclear weapons tests, and
vulnerability of microelectronics and other materials to cosmic rays.
"The lack of interference from cosmic rays, radio waves and other
disturbances that can be achieved at a Homestake laboratory represents a new
frontier of science," Lesko said. He pointed out that the large number of
tourists who visit Mount Rushmore and other Black Hills attractions provides
a unique opportunity to educate and interest millions of Americans in
fundamental science.
Marvin Marshak, a University of Minnesota professor who led a team that
visited four potential sites in the United States and existing underground
laboratories in Japan and Italy, said much cutting-edge science is being
performed deep underground.
"The United States has a chance to lead the scientific world with a
laboratory at Homestake in making discoveries about the fundamental laws of
physics, biology and geology," he said.
John F. Wilkerson, a University of Washington physics professor and a
committee member, said recent advances in experimental techniques have
enabled a new generation of more sensitive experiments aimed at a better
understanding of the basic framework for particle physics, called the
Standard Model.
"New experiments in the very quiet environments available very deep
underground will likely reveal new information that will help us understand
how to make the Standard Model a better description of the universe in which
we live," he said. "This U.S. laboratory will be unique. I expect scientists
from all over the world will come to this laboratory to collaborate on major
experiments."
The committee's report noted that although the Homestake site has
distinctive strengths, a second site studied, Mount San Jacinto near Palm
Springs, Calif., also could be developed into a world-class laboratory. The
committee preferred Homestake because of a lower initial cost to achieve
breakthrough science, a shorter time until the first experiments could be
performed, and fewer unknowns regarding laboratory development. The
committee noted that the Homestake Mining Corp. plans to close the mine at
the end of this year. The mine for decades was the largest gold mine in the
Western Hemisphere.
"The value of Homestake as a world-class laboratory site will diminish as
the closing process proceeds, so the committee is suggesting continued work
on Mount San Jacinto, and possibly some other mountain sites in the
California-Nevada region," Bahcall said. "The Homestake proponents need to
address transfer of the site to the state of South Dakota and a few other
issues rapidly, before the knowledgeable staff at Homestake leave the area."
The committee also visited and studied sites near Carlsbad, N.M., and
Soudan, Minn. Bahcall said that existing laboratories at both of those sites
are performing important underground science studies. However, he said,
those sites are not as deep as Homestake and Mount San Jacinto. Carlsbad
scientists said that they could not make deep excavations at their
laboratory without compromising the primary mission of the facility.
Wick Haxton, a physics professor who heads the UW's Institute of Nuclear
Theory, said the easy part of the committee's deliberations was deciding
that the United States needs a world-leading underground laboratory now. He
characterized the arguments for a laboratory as "absolutely compelling." The
hard part of the deliberations, Haxton said, was choosing among sites.
"Both Homestake and San Jacinto are stupendous, right up there. Homestake
has a time advantage. If they can line things up, that's great. Otherwise,
the U.S. will be first in the world with Mount San Jacinto."
Michael Wiescher, Professor of Physics at the University of Notre
Dame, emphasized that "an underground laboratory could house a
state-of-the-art accelerator that would simulate and probe the nuclear
processes that power the sun and other stars." With great enthusiasm,
Professor Wiescher stressed that the laboratory could study the same
nuclear processes at the energies at which the nuclear reactions
generate neutrinos in the sun and, in other stars, the heavy elements
out of which human beings are made."
The committee's work is supported by grants from the National Science
Foundation and the Office of Science of the U.S. Department of Energy.
Other committee members are Barry Barish, California Institute of
Technology; Frank Calaprice, Princeton University; Janet Conrad, Columbia
University; Peter Doe, University of Washington; Thomas Gaisser, University
of Delaware; Kem Robinson, Lawrence Berkeley National Laboratory; Bernard
Sadoulet, University of California, Berkeley; Henry Sobel, University of
California-Irvine; Michael Wiescher, Notre Dame University; and Stanley
Wojcicki, Stanford University.
Joe Wang of Lawrence Berkeley National Laboratory, a geophysics expert, and
Charles Nelson and D. Lee Petersen, consulting engineers of CNA Engineers,
Minneapolis, provided technical assistance during the committee's studies of
potential sites for underground laboratories.