On September 25, 1998, SIAL Gosciences Inc. (SIAL) was awarded Department of Interior, contract 98CRCN1018, by the U.S. Geological Survey. This contract required SIAL to carry out a high-sensitivity magnetic and electromagnetic helicopter survey over one block located in the Eureka Graben Area near Silverton, Colorado. The primary goal of this project was to provide digitally recorded and processed magnetic and electromagnetic data in order to evaluate geologic and hydrologic resources of the Eureka Graben Area. The base of on-site field operations was Silverton, Colorado. The survey was carried out by SIAL between May 27th and June 9th, 1999. This report describes the survey parameters, data acquisition and processing procedures, and products that SIAL delivered at the end of August, 1999. This website provides access to the data sets and documentation as delivered by the contractor.