Coal is important mineral resource in wisdom of diversification source of energy. Coal consumer in country is :
a. Power Station of Steam Power operated by Electrical Company of State
b. Cement factories
c. Others (Railroads Company, metal forge, industry)
Besides usage of coal for in country export coal increases also. Taiwan, Malaysia, Bangladesh and japan is the biggest consumer of Indonesia coal. As for area problem that is possibly happened as as result of exploiting of coal is at activity :
1. Mining Process
a. Underground Mining Process
Mining process of underground results the happening of three potential environmental impacts that is :
*) Mine water dismissal
*) Solid waste disposal, often contains coal and brimstone
*) Degradation of Surface of goaf soil; land; ground
b. Surface Mining Process
At surface mining process of area problem which there will be inter Alia :
*) Disturbance to soil ; land ; ground surface
*) Disturbance to ground water
*) The happening of air pollution because dirt, smoke of and existence of noise
2. Wash Process, Preparation and Storage
a. Cleaning of coal aim to dissociate coal from combustible or non flammable material like mix clay when mining. Wash waste water contains particle suspense and chemistry compound, when direct thrown to water territory can bother water territory biota.
b. Preparation of coal for example is break coal to become measure wanted when combustion. Area problem that is possibly happened that is air pollution by coal dirt.
c. Storage of coal can be done place of mining, port and place of coal usage. Area problem that is possibly happened is if happened burning spontaneously, dangerous dirt.
3. Transportation Process of Coal
a. Loads and unload coal when transportation, usage and others will generate air pollution by dirt.
b. Transportation of coal with ship results a few threats to sea-water and coast area. Arising problem was discard rest of coal cleaned by ship wash time.
c. Transportation with train and truck will generate a few air pollutions by coal dirt.
d. Slurry Pipe Line, yields big liquid waste of which can cause the happening of degradation of water quality. Water use at coal mud (coal slurry) in the end will be contamination with sprinkle water phenol and by condensation of coal particle.
4. Coal Usage
a. Power plant
Coal in gross applied at power plant will yield by-product in the form of gaseous emission waste of SO2, NOx, dirt and ash.
b. Cement
Coal applied to yield energy temperature for product clinker. When combustion, dusty is yielded in Cline. Fly ash exit from stack, while most of heavy ash one with clinker. Subject fly ash (fly ash) be main area problem to produce cement.
Other physical area problem of which can arise at coal mining is at place of coal heaping :
1. As process effect leaching happened by rainwater to surface of coal or forms condensation (leach) is having the character of acid which will seep to geology structure and can give pollution to ground water.
2. Most of Indonesia coal is including lignite type until bitumen is having the character of self- solvent burning (as of ldf combustibility) as oxidation effect which boosts up the coal heap Einstein characteristic temperature will.
In business to lessen impact negative as result of exploiting of coal starts from way of mining, transportation, depository and usage need to pay attention to local condition. Exploiting of coal as one of feeder energy alternative will lessen dependency of public to oil fuel.
Sources : Batubara & Gambut, Ir. Sukandarrumidi, MSc, Ph.D. Gajah Mada University Press