加拿大从坑内矿采出的矿石仅占年总产量的四分之一。但是,按金属或矿物含量而言,坑内矿的产量接近二分之一。1973年,房柱法、充填法和空场法占坑内开采的82％。房柱法用于缓倾斜的沉积矿床,例如萨斯喀彻温省的钾盐矿和安大略省伊利湖区的 The ore mined from pit mines in Canada accounts for only a quarter of the total annual production. However, in terms of metal or mineral content, pit production is close to one-half. In 1973, the column and column method, filling method and open field method accounted for 82% of the pit mining. The columnar method is used for gently inclined sedimentary deposits such as the Saskatchewan potash mine and the Lake Erie area in Ontario