Hole UA-1 was center punched (a small-diameter exploratory hole drilled ahead of the large-diameter emplacement hole) from 1,524.0 to 1,981.2 meters (5,000 to 6,500 feet) and hydraulically tested to determine an ideal location for mining a chamber. Fifteen zones were tested; minor amounts of water bypassed the packers during five of the tests. The tested intervals ranged in length from 37.5 meters (123 feet) to 211.5 meters (694 feet). For purposes of comparison relative specific capacities were calculated from comparable 60.4-meter (198-foot) intervals of tested rock, and ranged from 0.1162 cubic meters per day per meter (0.0065 gallons per minute per foot) of drawdown to 0.0039 cubic meters per day per meter (0.0002 gallons per minute per foot) of drawdown.
The interval 1,745.0 to 1,836.4 meters (5,725 to 6,025 feet) appears to be the best location for mining a chamber so far as water inflow is concerned. This interval, 91.4 meters (300 feet), consists of about 27.4 meters (90 feet) of breccia and 64.0 meters (210 feet) of basalt.
The inflow to a spherical chamber 18.3 meters (60 feet) in diameter and placed in the center of the proposed 91.4-meter (300-foot) interval, was calculated to be about 175 cubic meters per day (32 gallons per minute) after the first day and would stabilize at about 57 cubic meters per day (10.5 gallons per minute) after about 200 days.
