Geological investigation by the Bureau commenced late in July, 1948, and continued until the end of October of that year. The objects of the survey were to lay the foundation for future detailed studies of the mining field, to study the factors controlling ore localization, to assess the quantity and value of ore exposed to date, and to estimate the potential value of the field. In the search for orebodies, a knowledge of the geological factors can be of great assistance, and it is felt that the information given in this report and in the accompanying plans should be of considerable help in this respect. However, the prospector's methods - loaming, dollying, panning etc. are still quite fundamental to success in a prospecting field such as Tennant Creek and the suggestions made in this report are intended to supplement this type of work. The climate, topography, vegetation, gold production, general geology, and gold deposits of the area are described in this report. Detailed descriptions are given of the individual mines examined to date.