Deep Underground Science and Engineering Laboratory (DUSEL) Site Selection and Technical Design Development

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

The Homestake proposal presents a Conceptual Design Report in response to DUSEL Solicitation 3 (S3, NSF-06-614) that outlines plans for a Deep Underground Science and Engineering Laboratory (DUSEL) at the Homestake Mine, a gold mine no longer in active use for mining activities, located approximately 45 miles northwest of Lead, South Dakota. Title to the property footprint, buildings and infrastructure, and associated underground spaces for the proposed Laboratory approximately 186 surface acres, 800 underground acres, and associated mineral rights for the corresponding 7,700 acres - was transferred to the South Dakota Science and Technology Authority (SDSTA), an entity established by the State of South Dakota, which owns the property outright and in perpetuity. The SDSTA was created by the State to re-open the Homestake Mine and convert it to a dedicated center for science, engineering and education. The proposal requests funds to develop a technical design of the facility over the next three years, consistent the guidelines stated in S3. The proposal presents full and rich array of scientific and engineering questions that would be addressed by DUSEL, constituting a program of strong intellectual merit. The physics and astrophysical questions the proposal puts forward are the nature of dark matter; what neutrinos can continue to teach us; the matter-antimatter asymmetry evident today relative to the early universe and the possibility of CP violation experiments to address this issue; probing the fundamental stability of matter through study of proton decay; investigations of how the universe evolved through studies of the solar neutrino flux; and other topics of fundamental interest. Also discussed are studies of dark life underground that evolves in extreme conditions, through collaborative efforts in geomicrobiology, geochemistry, and biology; basic geoscience studies of rock porosity, strength, stresses, internal heat flow and other characteristics; in situ studies of coupled thermal, hydrological, chemical, mechanical, and biological processes on a large dimensional scale; hydrology and water purity; nuclear and other underground waste disposal; large-scale tests of subsurface imaging and mapping from surface detectors or boreholes, including seismic studies for elucidation of causes of earthquakes; and the creation of opportunities for important new intellectual synergies across disciplines. The education and outreach program is described in the proposal as having "two overarching goals: 1) to enhance understanding of, and appreciation for, scientific research among the general public; and 2) to leverage the resources of the laboratory to address well documented pipeline issues in science, technology, engineering, and mathematics, especially among under-represented minorities." It cites a broad list of issues and approaches to accomplish this, motivated in part by the identified need to enhance and maintain "American competitiveness and global stewardship" through education in technical fields (science, technology, engineering and mathematics.) Emphasis is placed on developing an approach to broader impacts that is intimately integrated with the development and aims of the facility. Accommodating easily accessed hands-on visitor experience in the underground environment is addressed, as are efforts to include historically underrepresented groups in areas of science and technology; science education for the general public; enabling DUSEL-related research for students; supporting K-12 teachers and recruitment for future teachers; partnering with regional institutions; developing economic opportunities by "enhancing the regional climate for science-related entrepreneurship and strengthening the local economy;" developing virtual environments to facilitate broader, non-local intellectual and educational connections; creating a supportive overall climate and infrastructure that encourages interaction with the DUSEL research community; and other ideas and strategies. The mine consists of an extensive series (~ 370 miles) of existing drifts and shafts, at approximately 60 levels, extending to 8,150 feet below ground; the proposal consists of using existing spaces and infrastructure upgrades and expansions to construct scientific and engineering work spaces to the deepest level. Principal research spaces are planned for the 300, 4850, 7,400 and 8,000 levels. The design calls for 10,000, 65,000 and 50,000 square feet of laboratory space at the 300, 4,850 and 7400 levels, respectively. Access to the 4,850 level is via two shafts (Ross and Yates), each capable of carrying an approximate nominal (maximum) 12,000 (13,400) pound payload and with similar maximum cage dimensions (~ 1.4X3.7X2.2m high); the No. 6 Winze, of similar capacity, provides access below these levels. An existing ramp system between the 4,850 and 8000 levels provides a path for secondary egress as well as an alternate transport path for equipment and construction materials. Primary excavations at the 4,850 level are in the Yates and Poorman rock formations, with construction traversing that boundary. The proposal requests approximately $15M in total funds over the next three years to develop a technical baseline design and associated project plan of the underground spaces and site infrastructure that would be needed to support the envisioned experimental program. The design realized by the team is expected to allow consideration of Homestake DUSEL for Major Research Equipment and Facilities Construction (MREFC) implementation.