This report is part of a seven-volume series on the Hanna, Wyoming, underground coal gasification field tests. Volume 1 is a summary of the project, and each of Volumes 2 through 6 describes a particular test. Volume 7 is a compilation of all the data for the tests in Volumes 2 through 6. Based on the recommendations of A.D. Little, Inc. in a 1971 report prepared for the US Bureau of Mines, the Hanna I test represented the first field test in reestablishing a field program by the US Bureau of Mines. The test was directed toward comparing results from a thick subbitiminous coal seam with those obtained during the field test series conducted at Gorgas, AL, in the 1940's and 1950's. Hanna I was conducted from March 1973 through February 1974. This report covers: (1) site selection and characteristics; (2) test objectives; (3) facility description; (4) pre-operation tests; (5) test operations summary; and (6) post-test activity. 9 refs., 10 figs., 4 tabs.