80-ia benefit

Coal gas and natural gas is different.

Under 80IA ,deduction is in respect of natural gas,but since for claiming deduction u/ said section required permission of Petroleum & Natural Gas Regulatory Board so also check whether they allowed coal gas or not. Further it had reached sunset date,now this exemption can be availed u/s 35AD only

As per Petroleum & Natural Gas Regulatory Board

"natural gas" means gas obtained from bore-holes and consisting primarily of hydrocarbons and includes-

(i) gas in liquid state, namely, liquefied natural gas and degasified liquefied natural gas,

(ii) compressed natural gas,

(iii) gas imported through transnational pipe lines, including CNG or liquefied natural gas,

(iv) gas recovered from gas hydrates as natural gas,

(v) methane obtained from coal seams, namely, coal bed methane, but does not include helium occurring in association with such hydrocarbons;

In my limited understanding Coal gasification is not required for obtaining coal seams,but they are doing that so they prolly are producing syngas. I don't have much information in hand to conclude anything. I need to know their process

Further 80IA is a thing of a past, if they were claiming this deduction then they must have approval of Petroleum & Natural Gas Regulatory Board. Why don't simply check that?

This you will have to check as whether clause v can be used in your favour

Text from wikipedia

Coal gasification is the process of producing syngas–a mixture consisting primarily of methane (CH4) carbon monoxide(CO), hydrogen (H2), carbon dioxide (CO2) and water vapor (H2O)–from coal and water, air and/or oxygen.

During gasification, the coal is blown through with oxygen and steam (water vapor) while also being heated (and in some cases pressurized). If the coal is heated by external heat sources the process is called "allothermal", while "autothermal" process assumes heating of the coal via exothermal chemical reactions occurring inside the gasifier itself. It is essential that the oxidizer supplied is insufficient for complete oxidizing (combustion) of the fuel. During the reactions mentioned, oxygen and water molecules oxidize the coal and produce a gaseous mixture of carbon dioxide (CO2), carbon monoxide (CO), water vapour (H2O), and molecular hydrogen (H2). (Some by-products like tar, phenols, etc. are also possible end products, depending on the specific gasification technology utilized.) This process has been conducted in-situ within natural coal seams (referred to as underground coal gasification) and in coal refineries. The desired end product is usually syngas (i.e., a combination of H2 + CO), but the produced coal gas may also be further refined to produce additional quantities of H2: