According to the British Petroleum Statistical Review of World Energy, 2013 , global coal reserves declined in the decade ending 2012: Figure 1. Proved coal reserves . Proved reserves of coal are generally taken to be those quantities that geological and engineering information indicates with reasonable certainly can be recovered in the future from known deposits under existing economic and operating conditions. If we look at supply and demand factors in the decline, we can see that: a) Coal price has grown significantly in the decade ending 2012 1 : Figure 2. Prices in US Dollars per tonne . b) Coal consumption has also grown significantly worldwide 2 : Figure 3. Coal consumption by region . c) The price of substitutes (i.e. Natural Gas) has also grown. Not so in North America though, but if we look at the world trend it is growing 3 : Figure 4. Natural gas prices . Therefore if the rule of supply and demand worked we would see increase i...