Today open-pit mining today accounts for most oil sands production. Huge pieces of equipment are needed to excavate and transport the sticky sand to extraction plants and upgraders to release the bitumen from the sand and prepare it for refining and market.

Before the oil sands can be mined, the overburden must be cleared away. Once removed, a portion of this layer of earth and sediment is stored for later use in land reclamation efforts.

Did you know? Using current technologies, only 19 per cent of Alberta ’s oil sands can be surface mined.

Giant shovels scoop up the sand and load it into massive trucks with hauling capacities of up to hundreds of tonnes. The trucks dump the oil sands into crushers, which break up large chunks and mix them with water to create a slurry. This slurry is transported by pipeline to the facility’s extraction plant, a process known as “hydro-transport.”

Truck and shovel mining is the most commonly used method of surface mining oil sands due to its low cost and high efficiency.

The bitumen content in an oil sands deposit varies from less than 1 per cent to more than 18 per cent of weight, a factor that can affect the economic viability of an operation: a deposit containing in excess of 12 per cent bitumen is thought to be rich, while less than 6 per cent is considered less viable.

The ERCB has established standards that oil sands developers must follow to extract as much bitumen as economically possible. Companies must mine the deposits containing lower concentrations of bitumen in addition to those with the best quality.

Extraction

At the extraction plant, the oil sands slurry (oil sands and water) enters a primary separation vessel where “froth” (a mix of air, water and bitumen) rises to the top, sand sinks to the bottom, and a blend of water, sand, bitumen, and clay (known as middlings) floats in the middle before going through a second separation process to extract additional bitumen.

Did you know? One of the earlier extraction methods involved mixing oil sands with hot water in huge tumblers to create the slurry, but the more efficient hydro-transport technology is phasing out the need for this step in the process.

The bitumen froth is further processed to remove more water and solids, then diluted, and finally passed through centrifuges, or inclined plate settlers, to eliminate the last of the water and solids.

The extraction process recovers more than 90 per cent of the bitumen fed to the plant.

The remaining sand from this process is used to fill in mined areas and aid in reclamation efforts. Tailings–water containing sand, clay, and other fine particles–are pumped into tailings ponds, while other wastewater is recycled back to the extraction plant for use in the separation process.

Upgrading

The nature of bitumen requires that its large molecules be split, or “cracked,” into smaller fragments. Adding hydrogen (hydro-cracking) or removing carbon (coking) creates smaller hydrocarbon molecules that are easier to process.

Cracking the bitumen generates gas vapours that must be separated and condensed into their liquid forms. The gases are sent to a fractionation tower, where they condense into three petroleum products: naphtha, kerosene, and gas oil. These products can be blended together or used separately.

Did you know? Developing the oil sands resource requires huge amounts of power. The utilities plant at an oil sands mining operation uses enough electricity to power a city of over 300,000 people.

The bitumen upgrading process removes most of the sulphur before the product is shipped to refineries, creating a sweet synthetic crude oil. The petroleum products are sent to a hydrotreater, where chemical impurities and trace metals are removed. This prevents the synthetic crude oil from changing its chemical composition while en route to the refineries.

Reclamation

Mining oil sands involves displacing huge amounts of earth to reach the deposit below, which can affect thousands of hectares of trees, wetlands, and other plant life. While the land is disturbed by development, oil sands companies are required to reclaim the land after the deposit has been mined out. Reclamation aims to return disturbed land close to predisturbance conditions.

As part of this effort to protect the environment, applicants of major projects are required to include an environmental impact assessment (EIA) in their ERCB applications. The EIA must include an outline of the environmental impact a project is expected to have, as well as a plan detailing how the company intends to reclaim the land once operations have ceased.

Generally, reclamation will include replacing the topsoil and repopulating the surface with trees, shrubs, and other vegetation indigenous to the area.

In Situ Development

In situ production involves drilling into the oil sands deposit when it’s buried too deep to be mined. To be produced from a well, the bitumen must be heated in order to draw it to surface.

Steam-Assisted Gravity Drainage (SAGD) involves horizontal wells–one above the other–that are drilled into an oil sands deposit. Steam is injected into the upper wellbore, heating the deposit and allowing the bitumen to drain into the lower well, where it is then pumped to surface.