Reconnaissance geological mapping of existing, previously quite productive opal workings in the White Hill area of the Stuart Range 'Breakaway' country, 100 km south-east of Coober Pedy, was followed by exploratory and infill narrow-hole auger deep drilling (200 holes for a total of 3431 m penetration) of the weathered Cretaceous Bulldog Shale section preserved beneath Tertiary silcrete cappings at the Teal Hole prospect. Some apparently promising discoveries of precious opal were made in two subareas of this prospect, which require follow-up evaluation by close-spaced delineation auger drilling and by Caldwell drill bulk sampling, to establish their viability for mining.