They lie about 8 kilometers by trail west of the village of Muzo in the Department of Boyacá, and embrace about eight great open cuts, closely grouped, occupying a portion of a steep walled valley, that of the Itoco, also called Quebrada del Desaguadero, an affluent of the Minero River which empties into the northward-flowing Magdalena, the great artery of commerce for central Colombia.