The most common approach to extracting metal-bearing ore from a porphyry copper deposit is by open-pitmining, although such mines also typically include some underground activities.
从斑岩含铜矿床开采含金属的矿石，最主要的方式是露天开采，尽管这种矿床常会伴随一些地下的地质活动。
2
Greenhouse gas emissions of tar sands crude are 40% higher than conventional oil, and the open-pitmining has devastated Alberta's boreal forest.
焦油砂的温室气体排放量比普通石油高40%，露天采矿已经极大地破坏了阿尔伯塔的北方气候带森林。
3
Mining operations at the existing openpit are due to cease by theend of 2012, although ERA is processing a proposal to develop the undergroundRanger 3 Deeps exploration area.