Zimbabwe has lots of coal. Necessity is the mother of invention. Last thing they need is getting involved with muslim dominated oil, when it appears the Chinese are moving in.
The cost of extraction of an energy resource can be calculated in units of energy required to extract the resource.
An example is carloads of coal extracted by using one carload of coal. 100 years ago one carload of coal would extract 100 carloads. Now one carload will extract 40 carloads. It shoud be evident that something is running down.
whos gonna shovel the coal? chinese?