Delineation of deposits. Coal mine survey in Buryatia
• Delineation of zones of different strength within a block. • Detection of coal horizon occurrence under overlapping deposits. The investigation was carried out along parallel georadar profiles directed along the site edge at 10 m distance between them. Profile №1 – closer to the edge. Profile №5 – farther from the edge. Scanning depth – 100 m Site №1 is located on a hitch 60-65 m beneath ground surface (absolute marks 783-785 m above sea level). Presumed (visible along the pit wall) depth of the coal horizon occurrence on Site №1 – from 10 to 30 m. During the works air temperature would go down to -45 ºС
- A coal horizon detected on Site №1. - The coal horizon is monoclinal, dipping at around 6 degrees. - The coal horizon is rising along the profiles from their beginning to the end. - The horizon roof is smooth, stable, well traced throughout each profile. - The horizon bottom is uneven, modified by a series of wavy irregularities of up to 10 m vertically and 25-30 m along the strike. - Thus, the horizon thickness fluctuates within a wide range and is 20 m on average (see Profiles 2-4). - The georadar sections carry data on geological boreholes drilled close to the profiles. - The coal horizon is modified by a breaking damage of discharge observed on Profile №1, at around 225 m.
Legend: 1 – airborne noise (Power lines, reflections from walls); 2 – dipping angle; 3 – objects (dead ground, sandstone) of various solidity; «orehole №2032 a – claystone, sandstone (alternation); b – sandstone; c – coal; d – black claystone. Site №1, georadar section №1
Site №1, georadar section №1
- An extensive normal fault, filled with sedimentary rocks, is registered in the eastern part of the site (in the beginning of the profiles).
The vertical displacement is around 30-40 m.
- Orientation of lateral deflection plane: south-east – north-east.
- Waste rock layers are registered in the upper part of geological section, differing from coal mass in rigidity.
- Obtained data is highly informative, well-detailed, and shows the position and shape of the coal horizon.
REPORT ON SURVEY RESULTS
1 – Airborne noise (electric transmission lines, reflections from walls, etc.); 2 – reclined bedding angle layer 3 – objects (dead ground, sandstone) of different rigidity; Borehole №2050: a – claystone, sandstone (alternation); b – sandstone; c – coal; d – black claystone
Site №1, georadar section №2
Determined (registered) fracture plane
Borehole №2059: b – sandstone; c – coal.
Site №1, georadar section №4
Wavy irregularities in the rock formation bottom filled with coal deposits
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