An Aboriginal band has threatened the very basis of Alberta's oil sands industry by filing a court challenge to the province's system of granting land tenure. A notice filed December 10th in Edmonton Court of Queen's Bench by the Athabasca Chipewyan First Nation claims that a series of oil sands permits the provincial government sold to Shell Canada and other companies are invalid. Selling off rights to explore the land without consulting area Aboriginals breached the Crown's duty to consult, say legal documents prepared by the First Nation.