Institut za rudarstvo i metalurgiju Bor

cal explorations and their evaluation must
be primarily done in accordance with the
operations of underground gasification.
UG on the environment could have an
impact on:
• Position
• Noise
• Emissions of gases into atmosphere
• Groundwater contamination
• Ground subsidence
Advantages of UG impact on a treatment
of layer are:
• The lack of dust on the surface
• Production of pure gas
• The achieved high efficiency in the
gas turbines
• The absence of gasifier on the surface
Disadvantages of UG impact on a
treatment of layer are:
• Underground contamination
• Surface contamination
• Process pollutants
Subsurface contamination
Groundwater contamination
There are several components linked to
the contamination of ground water, importance
of these components are monitored
and investigated in order to reduce and / or
eliminate risks and increase the importance
of factors related to contamination. Tests
have shown that a small percentage of phenol
and benzene were formed as a product
of underground gasification process.
Higher percentage with produced gas
comes to the surface where it is eliminated
in the process of purification. Certainly, the
rest passes through the surrounding layers
or was absorbed by the undistributed layers,
and the remaining is retained in the
so-called blown out cavities.
Permeability, hydrogeological and
geological structure of shale layer will
have the greatest impact on dispersing
contamination. It is of great importance
that the hydrology is completely known,
and structure itself will show where the
smallest possibility of contamination is.
The project have to exhaust completely
the most extensive exploratory
works related to the depth of coal layer
and monitoring before and after the gasification
process in a particular area.
The process products as the result of
oil shale combustion could have influence
on hydrology and groundwater quality.
Some of them are: dust, tar, charcoal, phenols,
benzene, methyl benzene, xylene,
boron, cyanide and hydrocarbons.
Leakage of gas from the cavities of
surrounding layers may be a problem in
the process of UG in the shallow layers,
i.e. subsurface layers. At the same time,
even in the conditions of gasification at
great depths, pollutants may reach the
surface by the ground water, along the
underground fractures of the ground. It is
vey important that the target area is as far
as possible from the existing mines and to
select mines at greater depth. In order to
minimize leakage or escape of gas, it is
very important to select the areas with low
permeability of the layers and control the
pressure during the process, to be as much
as possible close to the hydrostatic pressure.
Ground subsidence
Ground subsidence usually occurs
when you disturb the soil stability is disturbed
due to the UP in subsurface layers.
This primarily refers to the layers closer to
the surface, while in deeper layers the
effects are minimal. The fact is that the
depth reduces the effects of ground subsidence.
Surface contamination
Gasification plant located on the surface
includes: drilling heads, drilling
equipment, appropriate piping, processing
and injection / gas production plant, etc.
Impact on the environment may have the
following:
No 1,2010. 144
MINING ENGINEERING