DOI: http://dx.doi.org/10.1065/lca2004.04.157
Global Scope and Background. The study was aimed at presenting the methodology of the process eco-indicator, in relation to hard coal mines, and thereby making evaluation of the impact of the mine"s coal extraction process on the environment. The life cycle of a mine is made up of three phases: opening and developing the mine"s deposit, extraction of the mine"s deposit, closing the mine.
Methods. The assessment of environmental influence of mining operation of a colliery was executed on a basis of the life cycle analysis, in accordance with the standard series PN-EN 14040. The environmental loads caused by individual unit processes were calculated by means of the aforementioned methodology with division into the basic influence categories: human health, ecosystem quality and natural resources. The obtained values of eco-indicators for the individual unit processes made it possible to compare the unit-process-caused environmental loads. Mean values of the eco-indicators of the individual unit processes were calculated by means of the inventory analysis covering 38 collieries. Next, these indicators were used to compare environmental load values by each similar process in a colliery. A total eco-indicator was calculated for colliery by summing up the eco-indicators of the individual unit processes. The eco-indicators, structured as above, were calculated for the phase of opening out a deposit and for the phase of extraction.
Results and Discussion. The model mine in the phase of extraction of a deposit causes a total environmental load which expressed in points of the eco-indicator 99 amounts to 23.9 [MEw]. In the "human health" category losses amount to 8.4 per cent, in the "quality of ecosystem" 0.6 per cent and in the "resourses" category 91 per cent.
The greatest losses in all categories are caused by the process of getting body of coal and the next greatest ones are:
- In the "human health" category – cleaning coal at a preparation plant (250.0 kEw),
- In the "quality of ecosystem" category – cleaning coal at a preparation plant (25.0 kEw),
- In the "resources" category – entry driving by means of explosives (745.7 kEw).
Value of the eco-indicator 99 per 1 Mg (tonne) of coal extracted at the model mine amounts to 9.55 Ew.
On a basis of this methodology, calculations of the value of the eco-indicator 99 were performed for a real working colliery (extraction of 1.23 million tonnes in 2001). An inventory of characteristic quantities of individual unit processes connected with the extraction of this colliery was prepared. The total environmental load of this mine was 11.14 MEw (in the "human health" category losses amounted to 7.9 per cent, in the "quality of ecosystem" category 0.5 per cent, and in the resources" category 91.6 per cent).
The greatest losses in all categories were caused by the process of getting body of coal which amounted to 10.8 MEw, and next the process of driving a heading by means of heading machine which amounted to 130.9 kEw.
The value of the eco-indicator 99 for 1 Mg (tonne) of coal extracted in 2001 at the above-mentioned mine amounts to 9.06 Ew and is lower than the value of the eco-indicator 99 calculated for the model mine.
Conclusion. By means of the presented methodology it is possible to calculate environmental loads caused by individual unit processes with division into the basic categories of influence: human health, quality of ecosystem and natural resources. The calculated values of the eco-indicators of the individual unit processes enable to make comparisons of environmental loads and eventual decision making on changes in the ecological policy of a mine.
Recommendation and Perspective. The presented LCA methodology can be used to compare the operation of individual mines in the aspect of their influence on the environment. If the data of the same type with regard to unit processes are at disposal, then the mines can be ranked. Based on the LCA"s results, it is possible to make capital decisions connected with modernisation of specific production processes. |
