A detailed study of 16 drill cores surrounding the uranium zone in the Maybelle River area, in the southwestern part of the Proterozoic Athabasca Basin in Alberta, was undertaken to better define Athabasca Group sedimentology, stratigraphy and the alteration surrounding the deposit. The Athabasca Group sandstones constitute three third-order sequences: the Fair Point sequence (composed of the upper Fair Point Formation), the Manitou Falls sequence (composed of Manitou Falls c and d members) and the base of the Lazenby Lake-Wolverine Point sequence (composed of the Lazenby Lake Formation). The unconformity-type uranium-polymetallic mineral prospect is located at the base of the Fair Point Formation just above the unconformity and intersecting a graphitic mylonitic fault zone. Alteration features surrounding the uranium zone are similar in characteristic to those associated with deposits in Saskatchewan that have similar host rock alteration and metallogenic signatures. Petrochemical studies on drill core document a polymetallic assemblage of uranium, arsenic, nickel, boron, phosphorus, molybdenum and cobalt, in decreasing order of abundance.