Development of uranium exploration methods using adon

This report gives the results of tests carried out during the 1968 field season to determine the applicability of the radon method for detailed prospecting for uranium. Radon tests in surface waters and in soils were carried out in three different geological environments; the Gatineau Hills, Quebec, and Sudbury and Elliot Lake, Ontario. In the Gatineau Hills, seasonal variations, variations with depth of lake, with distance from shore, and with distance from uranium occurrence along shore, were studied. The results suggest that surface and underground water drainage is responsible for the radon and radium in the lake systems. Where the overburden is one or two feet thick on-site radon and thoron determinations in soil emanations in the Gatineau Hills outlined radioactive pegmatites somewhat more clearly than did gamma-ray tests. Although radon levels varied by a factor of two, anomalies related to source were detected throughout the field season. A radon anomaly, detected in a reconnaissance survey of the surface waters of the eastern quarter of the Sudbury irruptive, appears to be similar in origin to the anomalies investigated in the Gatineau Hills. Radon and gamma-ray levels across the copper-nickel ore borders were comparatively low and meaningless. In the Elliot Lake area the distribution of radon in four lakes was studied; two in the contaminated westward drainage channel of the southern limb of the Quirke syncline, and two in uncontaminated terrain overlying the uranium-ore-bearing Matinenda Formation. The results from the contaminated lakes demonstrate some of the principles of the radon prospecting method very well except for the fact that man, rather than nature, introduced the radium which gives rise to the high radon levels in the water system. The radon levels in the uncontaminated lakes are at least a factor of ten lower than in the contaminated lakes, and straddle the sensitivity limit of the instrument. Some shallow creek deltas are reflected in the radon profiles 50 feet from the mouth of the creek and hence could serve as starting points for regional investigations. Relative to the lakes in the Gatineau Hills, the radon levels in the two uncontaminated lakes in the Elliot Lake region are low. Regional backgrounds, rather than absolute radon levels, must therefore be employed to determine anomalies. On-site radon determinations in soil emanations across the uranium ore zone at the Rio Algom Quirke Mine outline the ore zone more distinctly than do gammaray determinations. Soil tests across the projected contact of the Matinenda Formation in the southern limb of the Quirke syncline gave a negative anomaly at the contact. In general the investigations have shown that depending on the medium and sampling density employed, the radon method can outline radioactive sources on a reconnaissance scale as well as on a more detailed scale.