TV:BIP Ratio Explained: The Economics of Oil Sands Mining
In order for surface mining to be economically feasible, the ratio of waste material (or overburden) to oil sands ore must be relatively low. As the oil sands deposit gets deeper below grade, more and more overburden must be removed before the valuable oil sands. Most mined oil sands deposits are located within 50 meters from the surface.
The strip ratio (SR) is the simplest measure of mining efficiency. Defined as the weight of overburden (or waste ore) divided by the weight of oil sands ore, a strip ratio of 2 is considered high but feasible if the ore grade is high enough.
A better measure of mining economics is the TV:BIP ratio.
TV:BIP is a ratio of the total volume of oil sands mined (TV) to the total amount of bitumen in-place (BIP).
Since mining vehicles and conveyors are equipped with weightometers, mining metrics are typically measured in tonnes, not volume. If the bitumen grade of the oil sands and the strip ratio is known, the TV:BIP ratio can be calculated as follows:
Rearranging the above equation → OBv = OSv × SR [Equation 1]
Replacing OBv with Equation 1:
Substituting approximated densities for bitumen and mined oil sands:
- Density of bitumen = SGbit = 1.0 tonne/m³
- Density of oil sands = 2.1 tonne/m³
Rearranging the above equation → OSw = OSv × 2.1 [Equation 2]
Replacing OSw with Equation 1 and assuming the SG of bitumen = 1:
Finally, TV:BIP can be calculated from the strip ratio (SR) as follows:
The Alberta Energy Regulator (AER) requires any section of the deposit with a TV:BIP ratio less than 12 to be mined. Anything lower cannot be wasted or stockpiled. In some cases, if the ore grade is high enough, a TV:BIP ratio greater than 12 may be economical to mine. This would generally be only for high-grade deposits and only at the discretion of the mine operator.