Denison Mines Corp.
Method of Surface Borehole Mining Using Horizontal Drilling Techniques

Abstract:

A method of horizontal directional drilling is provided. The proposed method utilizes directional drilling in which boreholes are arranged in a pattern such that the surface area of extraction is maximized. The pattern can be achieved using a vertical borehole, multiple lateral boreholes and multiple subsidiary portions of the lateral boreholes. A lateral borehole is drilled extending beyond a vertical borehole towards the orebody, from which a subsidiary borehole is drilled into the orebody. Once the extraction is complete, the subsidiary borehole is back filled. A new subsidiary borehole is drilled extending beyond the lateral borehole and adjacent to the first subsidiary borehole. The subsidiary boreholes are planned to form a honeycomb or direct stacked pattern. Once all extraction is complete from a lateral borehole and its subsidiary boreholes, a new lateral borehole is drilled from the vertical borehole and the process is repeated.