The Mineral Character and Geomechanical Properties of the Transitional Rocks from the Mesozoic-Neogene Contact Zone in the Bełchatów Lignite Deposit

Purpose Beginning more than 30 years ago, opencast lignite mining in the "Bełchatów" area is an important source of accompanying minerals. Lignite mine yields, on average, 35 million tonnes per annum and requires removing 110 cubic meters overburden. Therefore outside main mineral exploitation lignite, leads to a large-scale economy Part minerals are present overburden exposed slopes mine; these selectively exploited event absence recipients stored anthropogenic deposits. The object this mineralogical-geochemical study group transitional rocks such as opoka-rocks, gaize marls when contact occurs between Neogene sediments Mesozoic basement deposit. In case rocks, during preliminary geological research carried out mine, doubt often appear their explicit petrographic character hence practical use. Advanced mineralogical methods allow mistakes identification be avoided geomechanical indicates possible direction Methods heterogeneous examined required use broad spectrum. following microscopes were used framework research: Polarizing Olimpus BX51 electron (SEM) FEI Quanta 200FEG equipped with X-ray spectrometer (EDX Genesis) backscattered detector (BSE). addition, observations using cathodoluminescence apparatus, Cambridge Image Technolgy Ltd CCL 8200 mk3 model, polarizing microscope, type Nikon Optiphot 2. Determination phase composition (qualitative quantitative) was made diffraction utilizing powder method Debye-Sherrer. An diffractometer, Philips PW 3020 X'PERT, also study. Analyses by Fourier transmission infrared spectroscopy performed production apparatus BIO-RAD, model FTS 165, package programs for digital processing results. chemical determined atomic absorption (AAS) spectrophotometer PU 9100Xi Camera SX-100 emission inductively coupled plasma (ICP AES) 40 PLASMA. properties accordance standards: open total porosity (PN-EN 1936:2001) compressive strength air – dried state 1926:2001), bulk density 1936:2001), relative humidity 1925:2001); absorbability stone material 13755:2002) abrasion face Boehme (PN-84/B-04111). Results Mineralogical-petrographic studies showed that dominant component SiO2 which presented form opal A CT, chalcedony, quartz microquartz. it found studied had been covered secondary mineralization processes. underwent primary silicification decalcination processes, contributed diverse nature secondarily experienced change physico-mechanical properties. silification process result diagenetic processes taking place within argillaceous occurring sub-coal series situated immediate vicinity bedrock. There release extruded silica-rich water from clays mechanical compaction process. Some amounts silica may derived plagioclase dissolution transformation terrigenous material, mainly grains potassium feldspar. precipitation porous solutions occurred most coinciding presence carbonic acid formed decomposition organic substances vegetable origin. Practical implications have significant implication, deposit can building materials. Originality/value Against background number published papers seams there lack mineralogical-petrographic Mesozoic-Neogene zone into account aspect raw This paper has produced fill void area.