Hydrological, Geological, and Biological Site Characterization of Breccia Pipe Uranium Deposits in Northern Arizona

摘要

In the late 1940s and early 1950s, uranium was discovered in association with many of the old copper mines in the Grand Canyon region, hosted by geologic features called breccia pipes. Discovery of high-grade uranium ore in the Orphan Lode (breccia pipe) deposit led to uranium mining on patented claims within the Grand Canyon National Park from 1956 to 1969. In the 1970s, breccia pipes became the subject of intense exploration in the Grand Canyon region, sought for their uranium ore potential; several were found exposed in the plateaus and the walls of the Grand Canyon and its tributaries. In the 1980s and early 1990s, uranium was mined from seven breccia pipes in the northern Grand Canyon region. Today, some of the highest grade uranium ore in this country is believed to be located in the many mineralized breccia pipes scattered across the Grand Canyon region. On July 21, 2009, U.S. Secretary of the Interior Ken Salazar proposed a two-year withdrawal of about 1 million acres of Federal land near the Grand Canyon from future mineral entry. These lands are contained in three parcels: two parcels on Bureau of Land Management (BLM) land to the north of the Grand Canyon (North and East Segregation Areas) and one on the Kaibab National Forest south of the Grand Canyon (South Segregation Area).