Introducing the IDEF0 Methodology in the Strategic Planning of Projects for Reclamation and Repurposing of Surface Mines

The closure of surface mines is a complex framework characterized by extended reclamations of post-mining sites towards an environmentally friendly and sustainable land-use system development with beneficial returns to society and the economy. The paper demonstrates the critical mine closure problem, draws research questions, and introduces the IDEF0 (Integrated DEFinition Function) process modelling method as a low-cost and easy development tool for use by mining experts to perform strategic planning of sustainable mine reclamation and repurposing projects. A case study for the method applied in a Greek lignite mine is presented.

The Setting of Strength Parameters in Stability Analysis of Open-Pit Slope Using the Random Set Method in the Bełchatów Lignite Mine, Central Poland

The slopes of open-pit mines are often at risk of failure. To identify this hazard, stability analyses are performed. An important element of these stability analyses is the reliable selection of input parameter values for the calculations. This selection is difficult because the slopes of the open pit are disturbed by mining activities. In such conditions, rheological processes, intensified by weathering, develop in open-pit slopes. This study is aimed at setting the strength parameters for the stability analysis of open-pit slopes with a developed slide process, using the random set method. The study was performed on the example of the open pit of the Bełchatów lignite mine, central Poland. A four-stage methodology, according to the random set method, was proposed. The methodology covered the following: site investigation, sensitivity analyses, shear strength reduction (SSR) analyses using numerical calculations, and probability analyses of the factor of safety (FoS) calculation results. The setting of the input parameters took into account the peak and residual strength parameters for each lithological unit in the physical model of the open-pit slope. Samples for laboratory tests were taken from the cores of nine test boreholes. The sensitivity analysis included all peak and residual strength parameters for each lithological unit in the body. As a result of the sensitivity analysis, specific strength parameters were adopted that would have a great impact upon the results of the calculations. Selected sets of parameter values were then used for the FoS calculations. The resultant FoS values revealed the probable slide planes. The positions of the slide planes were consistent with the interpreted slide surfaces based on the control boreholes and terrain observations. Knowledge of the slide planes positions and the values of the strength parameters enabled the designing of a securing approach for this landslide, and the taking of preventive measures to reduce this risk.

Surface identification of undermined spaces with the use of soil radon emanometry

Several surface geophysical methods were used to study the displays of undermined spaces in their physical fields and to try to distinguish undermined from non-undermined parts of underground mining area. The studied area of the Čáry lignite mine in the Western Slovakia represents an actively subsided place with high risk to the population. Despite very low radioactivity and relatively high gas permeability of building geological formations, the results of soil radon emanometry show the possibility of radon gas accumulation inside the undermined spaces, but their permanent subsidence causes loosing of overlying material and escape of radon gas. The boundaries (edges) of undermined and sunken areas were identified as the only places with increased values of 222Rn activity, probably due to the presence of vertical supporting mine walls allowing radon gas accumulation and upward movement. Thus, the soil radon emanometry clearly indicates the borders between undermined or sunken and non-undermined parts.

Characteristics of Clay Raw Materials from the Turów Lignite Mine Waste, Poland: Potential for Industrial Applications

Considering the diversity of clay raw materials, we can distinguish their numerous varieties using genesis and retention conditions, as well as specific physical, chemical, and thermal properties as criteria of division. Three samples of fine-grained clay materials, collected randomly from the Turów lignite mine tailing piles, were subjected to testing for their grain and chemical composition and specific surface area. The results show that the tested materials are non-porous adsorbents. Additionally, a thermal analysis was carried out with a simultaneous quadrupole mass spectrometry (QMS). In the tested samples, the weight loss associated with the release of water from the clay was observed in two temperature ranges: from 40 to 240 °C (physically bound water) and from 330 to 620 °C (structured water). The weight loss associated with the decomposition of organic matter was registered in the temperature range of 300 to 560 °C. The results of the conducted tests might provide the basis for further analysis of the potential use of these materials as heat stores, components of insulators, or additives of ceramic products.

Efficiency Analysis of Lignite Mining Operations Using Production Stochastic Frontier Modeling

This paper proposes a stochastic frontier model for measuring both technical and environmental performance at the mine level by using a translog production function. The Kardia Field opencast lignite mine of the Greek Public Power Corporation (PPC), S.A. is the topic of the case study. Efficiency ratings are derived over a long period of time using annual operating data, and in addition, the determinants of inefficiency are established by means of the technical inefficiency effects model. In the light of the results, there is a strong correlation between technical and environmental efficiency; the results are validated by those produced by data envelopment analysis (DEA). In addition, the stripping ratio is identified as the statistically significant determinant of performance. The proposed framework could be used as an instrument to measure the efficiency of lignite mining operations and to identify the drivers of performance.

First two cockroaches from the early Eocene of western Rajasthan, India (Insecta: Blattodea)

We describe the first two Blattodea from the early Eocene Palana Formation of the Gurha opencast lignite mine, western Rajasthan, India. Although it is not possible to attribute them to a precise family, these large wings suggest a warm and humid paleoclimate for the area at that time.

Risk assessment of flooded equipment revitalization on opencast coal mine Tamnava-West Field

Unprecedented floods in 2014 caused huge consequences on Serbian lignite opencast mines, such as halt of coal production and damages of the mining equipment. Three equipment revitalization options were urgently assessed to continue with coal production on opencast mine Tamnava-West Field. This paper compares the economic risks of the three investment options for lignite mine Tamnava-West Field mining equipment revitalization, based on this experience and probable risk of a repeated event. The results of the detailed quantitative risk analysis should verify the urgent decision and ranked with a multiple-criteria decision analysis.