The Bureau of Mines is conducting research on advanced mining methods that will help the mining industry meet world competition into the 21st century by methods that maintain or increase productivity, have lower costs, and still meet stringent environmental requirements. A major focus of this effort is in situ leach mining methods, where leach solution is injected by wells drilled from the surface or underground working into an otherwise undisturbed ore zone; dissolution of mineralization as the solution moves through fractures and pores, or diffuses through the ore; recovery of metal-bearing leach solution through recovery wells; and solution processing at a surface plant. Successful in situ extraction of uranium from porous Texas and Wyoming sandstones since the mid-1970's coupled with the demonstrated leachability of copper oxide ores using in situ methods in shattered ore (block-caved zones and backfilled stopes) suggested the possibility of leaching copper oxide ores in place. In 1986 the Bureau began a research project to develop in situ mining methods for shallow to moderately deep copper oxide ores using h2so4 leach solution. The focus of the present research is on the control, collection, and detection of leach solutions; gangue-mineral relationships; copper recovery and acid consumption; and engineering design. This paper highlights the field program, which involves a government-industry cost-sharing program; the use of geophysical techniques to detect leach solutions, and the use of drilling additives to enhance drilling performance.