This paper describes an experimental program financed by the Bureau of Mines for the development of an in-line cooler using direct water- to-air contact heat exchange. The direct water-to-air contact design eliminates problems of dust buildup on cooling surfaces, a frequent problem of fin-coil coolers in mines. While direct-contact coolers such as spray chambers are relatively tolerant to dust loading, their thermal performance, in practice, has not been viewed in the United States as competitive with counter-flow, fin-coil-type exchangers. This is believed to be due to the negligible experience with the direct water-to-air coolers in North American mines. The purpose of this paper is to describe a successful experience with a water spray-type cooler. The program consisted of resolving initial specifications, design, development of the cooler including laboratory testing and in-mine testing at the Homestake gold mine in South Dakota.