7.4.3 Field data collection
Questionnaires were communicated to different CMAs with a request to fill-up
these to get data on LUP in each individual CMAs for two different time levels,
i.e. 1994 (a time after about 100 years of coal mining in India) and previous
(as back as available) to know the condition of days nearest (as far as possible)
to pre-mining days, in order to get data on LUP of the area before any disturbance
and after disturbance through about 100 years (as far as possible).
Parallelly, information were collected on different natural and human/social
characteristics of the respective areas which could have some control on LUP
of the area. These are related to geology, topography, water availability, soil
(quality and thickness), population (density and income) etc. over the region
and also the life, depth, nature (opencast or underground) and area of mining.
Data could be made available from 31 CMAs.
7.4.4 Data processing and analysis
Attempt was made to deal with the data on LUP, as was received from CMAs. From
the received information the land-cover/-use types, as could be visualised in
different CMAs were grouped into six groups, namely forest-cover (F), cultivation
lands (C), built-up areas (B), mining areas (M), water bodies (W) and others
(O) to include barren lands, stony lands or any other not falling into any of
the other five types mentioned.
These processed data were analysed to study whether the CMAs have suffered any
change in the components of LUP through past years. The change was studied with
reference to the above listed six components, which obviously varied from sample
to sample.
As the sample size was more than 30, it was definitely a normally distributed
sample. As per the standard concept of normally distributed population (Kreyszig,
1999) this sample was well suitable for statistical analysis of the population
to reveal a reliable result. Thus from this data it could be possible to study
the change in LUP if any, experienced by the CMAs in past years, and its significance.
The 31 samples available representing the population were first analysed individually
to record the change experienced by each of the above referred components of
LUP through the time span between the past days (for which the data could be
made available) and 1994 (the actual time span covered varied from sample to
sample). The observations for two randomly chosen samples have been presented
pictorially in Figs. 7.2a and 7.2b. Field experience on the subject indicates
that the quality and quantity of alterations may be different by OC-mining and
UG-mining; this fact had also been given proper importance during assessment.
Analysis of the total population revealed that forest cover in CMAs went on
decreasing through the period under consideration. Further, among the UG-mining
areas only in one(1) case forest cover had increased and decreased in (fourteen)
14 cases. While among the OC-mining areas forest cover decreased in thirteen
(13) cases, remained same in three (3) cases and increased in none. When studied
mathematically, the overall change in forest cover was noted as -0.37 for 31
samples (/yr.).
Whenever mining is conducted in any area, the previous land-use gets disturbed
and the area retains its use in mining. In the present case also the amount
of land being used for mining went or increasing. However, among the 31 cases
studied, the amount of land in mining use had been noted to experience slight
decrease in 1 case of UG-mining and in only 1 case of OC-mining, no change in
9 cases of UG-mining and 4 cases of OC-mining while in other 16 cases it had
increased. When calculated for the total population the change in the quantity
of land being used for mining resulted to be 0.63 for 31 samples (/yr.).
Similarly the data for agricultural land, built-up land water bodies and others
were processed and analysed.
7.4.5 Assessment of LUP change
As the next step of activity, changes (through time) in the amount of land area
by the different components of LUP in CMAs were considered statistically with
an attempt to find out the trend of change.
There are concepts and procedures of environmental impact assessment (EIA) of
mining activities which takes into consideration all the visible and tangible
effects. All land-use plans or land reclamation plans which are developed for
mining areas, necessarily take care of the findings of such EIA. The present
study revealed that there remains something beyond the scope of such EIA, hence
plans based upon that suffers from some "lacuna". Hence, this study tried to
account for all types of impacts of mining on LUP of CMAs and the surroundings
by considering matters in a holistic manner to include the visible and invisible,
direct and indirect, also tangible and intangible, short term and long-term
impacts, upto 100 years or more in some cases. This followed from the fact that
damage to land and LUP by mining and related activities are both short term
and long term, not all visible, some are intangible but multiplies themselves
through time as revealed by the land degradation cycle (Ghosh 2002) detailed
in Fig. 3.2. Some such idea could be drawn to some extent from the comments
of Banerjee (1982) as he explained that the area of influence of environmental
disturbance by coal mining is more than 10 times the area directly damaged by
mining.
In the above background the follow-up action of the research was planned with
the basic purpose to assess the actual quantity of each LUP components altered
to some other land-use in CMAs through time (the maximum span for which data
could be made available in respective areas) and to establish the trend of change
in LUP.
The summary of findings obtained may be listed as follows:
* Forest cover in these areas went on decreasing through time for both OC- and
UG- mining areas; when studied mathematically, slope of the line representing
the overall change (per year) in forest cover was -0.37 for 31 samples.
* Agricultural land in these areas went on decreasing through time, further
when visualised for OC- and UG- mining areas separately, it was noted that the
decrease is more prominent in OC- than in UG- mining areas. When calculated
statistically, the overall change in amount of cultivation land (per year) came
out to be -1.69 for 31 samples.
* Built-up lands in these areas went on increasing with time in general and
for both OC- and UG- mining areas. When analysed critically, the overall change
of built-up lands (per year) for 31 samples resulted to be 0.31.
* For water bodies and aquifers, mining is a damaging activity but if unfilled,
the depressions created by mining may generate some surface water bodies; this
was revealed by the fact that amount of area covered by surface water bodies
had suffered a very nominal change in most of the cases. Further, when calculated
the overall change (per year) in land occupied by surface water bodies was 0.03
for 31 samples.
* The land-use recorded as "others" contains many components thus revealed varied
facts. However, in general mining damages green cover and increases danga/barren-land.
When studied critically, the overall change (per year) in this category of land-use
amounted to 1.01 for 31 samples.
* While mining is the main activity causing the above changes in LUP, it is
obvious that as mining proceeds, the amount of area under mining use increases.
When calculated statistically, the overall change (per year) in amount of area
under mining-use resulted to be 0.63 for 31 samples.