The Alberta oil sands are extracted by either surface mining, or in situ recovery. Typical extraction processes (i.e. simple drilling and pumping) are not feasible because the bitumen is interspersed with sedimentary materials and water. Surface mining is suitable for only the small portion of the oil sands that lie under 75m or less of overburden. (In situ recovery techniques are necessary for oil sands that are more deeply buried.) The first step of surface mining is to drain and remove the muskeg, and remove the overburden. The oil sands are then scooped up, crushed and transported, via conveyor belt or truck, to the extraction plant. At the extraction plant, the oil sands are processed to separate the bitumen from the sand (primary extraction), and to remove water and fine particles. The raw bitumen is then upgraded, prior to being pumped away for refining.

The vast majority of oil sands are not suitable for surface mining and must be extracted via in situ recovery. The most productive in situ method is steam-assisted gravity drainage (SAGD). Fireflooding and electrovolatization are alternate in situ recovery methods, but they are not as commonly used as SAGD. In SAGD, high pressure steam is injected into the oil sands through vertical shafts. The heat and water from the steam permit the bitumen to flow, and it is pumped from the wells. The bitumen is then upgraded.

The extraction process separates bitumen from much of the sand, clay and other materials. Air is added to the slurry, which is then pumped to large gravity separation vessels. The bitumen attaches to the air bubbles and rises to the top to form a bitumen-rich froth. This froth is processed through a stripper, which removes the air bubbles and directs the bitumen to two large froth storage tanks. The sand particles settle to the bottom and are pumped to the tailings processing system. A middle stream off the gravity separation vessels is processed through a flotation system to optimize bitumen recovery.

The Upgrader processes the bitumen into vacuum gas oil and a synthetic crude oil. There are many different variations on upgrading technologies, but they generally fall into one of two broad categories: carbon removal or hydrogen conversion. The Project will use a hydro-conversion process rather than the traditional coking process used to upgrade bitumen.

Hydro-conversion is an environmentally-friendly process as it eliminates the need for coke disposal and produces a higher yield of crude oil than traditional coking methods.

Source: Western Oil Sands, http://www.westernoilsands.com; Cantox Environmental, http://www.cantoxenvironmental.com/