In order to meet the demand of recovering the "three unders" coal resources (under buildings, under railways, and under water bodies), the technique of blinding-hole underground coal gasification (UCG) is presented and its method is briefly explained in the paper. We did not merely explain the model experiment platform, experiment system, and process, but also analyzed the experimental results. The measured results indicate that the nature of gasification agent influences the temperature distribution of the gasifier as well as gas composition and heating value. According to the experimental results, on the condition of blind-hole gasification, when the gasification agent is air, oxygen-enriched air, steam with oxygen, and steam free of oxygen, the heating value of the gas is 3 3.46-5.75, 3.93-10.48, 8.3-11.0, and 9.17-14.51 MJ/m(3), respectively. The coal body around the gasifier (under the effect of high temperature), its organizational structure, and surface morphology have altered completely and formed the so-called dry distillation composite arches, which consist of porous zone, semichar zone, and char zone. As a result, the formation of the composite arches improves the physical and mechanical intensity of the coal body and the overall loading capacity and the integrity of the coal body around the gasifier. Thus, the blinding-hole UCG enables the recovery of the "three unders" coal resources, which, undoubtedly, lays an important theoretical foundation for the commercial-scale production of the UCG. (C) 2003 Elsevier Science B.V. All rights reserved.