This report describes the field tests conducted at the Santa Cruz joint venture site (jointly owned by Asarco Santa Cruz Inc. and Freeport Copper Company) in Casa Grande, Arizona. These tests were carried out in existing core holes sc-46 and sc-19 and include coring; water injection permeability measurements; geophysical wireline logging measurements of initial water saturation, porosity, and flow profile; and laboratory core leaching. The purpose of these tests is to provide supporting data for the commercial-scale operation and experiment designs. Coring and testing in sc-46 was conducted over the interval from 1,436 to 1,685 ft, and in sc-19 from 1,249 to 1,461 ft. Field test results indicate the following average properties: 1 md in sc-46 and 4 md in sc-19 with mud damage in the test interval, and 20 to 30 md in sc-19 where the test interval did not have mud damage; 8-pct porosity in sc-46 and 9-pct in sc-19; 100- pct water saturation in sc-46 and in sc-19. Preliminary laboratory core leaching data indicate that at 50-gpl sulfuric acid strength 10- gpl copper loadings are achieved at a net acid consumption of less than 3 1/2 lb acid per pound of copper. These data are within the range of input parameters used to calculate the economics for the best mining scenario for the commercial design in Volume IV.