Coal is cheaper than oil and natural gas. Coal don't need processing like oil and natural gas do. Plus coal is only a few hundred meters down.
Coal can provide 20% of Pakistan's electricity. The rest can be handled by natural gas, nuclear, wind, solar, hydroelectric.
Most low-grade coals (with low carbon content) need some kind of processing for the removal of non-combustible matter. This is especially true for the coals used in the metallurgical processes.
For power generation, bituminous or semi-bituminous coals can be used without processing. However,
the coal under discussion here is 'Thar Coal'. This is "Lignite" or brown coal which is the lowest grade of coal. It has about 35% moisture content and hence needs to be processed (dehydrated) before it can be used for burning.
This makes it expensive to mine, store, and transport and has very high carbon emissions when burned. That is why power stations using lignite coal are generally situated close to the extraction site.
FYI even though lignite is primarily used for power generation, I have come across lignite briquettes (dried cake)
used for domestic heating. Lignite can also be used to produce "syngas" (a mixture of hydrogen, carbon monoxide & carbon dioxide) which can be burnt in power plants and /or manufacturing synthetic motor fuels.
The main point here is to emphasize that Thar coal needs processing before it can be used. We have not been told d the cost per MMBtu of the processed Thar coal. It may not be cheaper than LNG in Rupee terms but it would surely save a lot of foreign exchange.