Empirical Correlations of Longwall Subsidence Data for the Illinois Coal Basin

Subsidence, mining and site data has been collected over a number of longwall panels in the Illinois Basin. Using this data, empirical correlations are attempted to various subsidence parameters, including maximum vertical and horizontal displacement, subsidence slope and curvature and horizontal strain. Also, the corresponding locations of these various subsidence characteristics are correlated to the associated site conditions. An extensive list of definitions are provided for the various subsidence parameters utilized in the paper

Significant uncertainties in Pennsylvanian correlation in Illinois coal basin

"Reprinted from the Bulletin of the American Association of Petroleum Geologists, vol. 23 no. 10 (Tulsa, Oklahoma, October, 1939), pp. 1507-1524.

Dependence of the maximum surface subsidence from setup entry distance

Based on the subsidence data collected through a comprehensive subsidence monitoring program conducted over longwall in the Western Donbas coal mines, graphical model has been proposed to predict dynamic maximal subsidence in the Western Donbas coal basin

Prof Saf

YLH8/Intramural CDC HHS/United States2015-10-02T00:00:00Z26435556PMC459118

Johnston City School, Mine Subsidence or Shallow Foundation Problem?

Johnston City, a small community in southern Illinois, lies above the Herrin (Illinois No. 6) coal seam. The community has experienced sporadic episodes of surface subsidence due to the collapse of underground mines since the 1930\u27s. Although the mining company left a large block of coal beneath the town\u27s elementary school to prevent subsidence damage to the structure, large cracks appeared in the school building in December, 1971. After the building was razed, construction of a new school was initiated in 1974. Approximately six months after the start of construction, new evidence of structural distress was observed in \u27the still-uncompleted structure. Construction was suspended indefinitely while site investigations were conducted. These investigations, along with recent air photo studies, indicate that renewed mine collapse and the resulting downward displacement of the surface, were the cause of this second incident of structural distress

Using a computer spreadsheet to characterize rock masses prior to subsidence prediction and numerical analysis

"To characterize rock mass overlying high-extraction coal mines, the USBM utilizes a computer spreadsheet program and modified Rock Mass Rating (RMR) system. The spreadsheet calculates an RMR based on a bed's engineering properties determined from core logs and laboratory tests. An in situ deformation modulus and a bending stiffness are computed for each bed. Stiffness-versus-depth plots identify groups of beds with similar stiffness. Large variations in stiffness between adjacent beds are considered significant horizontal discontinuities where slip is likely. Time domain reflectometry (TDR) is used to verify this hypothesis by measuring shear displacement along such discontinuities. A model of the overburden is built by assuming that a near-surface laminated beam exists above a transition zone in which large plastic slip occurs along horizontal discontinuities. Increasingly thicker groups of beds are modeled to determine the most probable beam thickness based on a comparison with measured deflection profiles." - NIOSHTIC-2NIOSHTIC no. 2003937

Geomechanical and weathering properties of weak roof shales in coal mines

Many coal seams have weak shale immediate roofs that cause ground control problems. Therefore, it is important to know the mechanical properties of these shales so that preventive measures can be developed in advance. However, it is sometimes hard to understand this rock type due to its unpredictable behavior. A good example of this situation is found with the shale roof strata in two coal mines located in the Illinois coal basin---Herrin No. 6 seam. Although these mines are located very close to each other, one of them has many roof falls, whereas the other has no measurable ground control problems.;The aim of this thesis is to explain why and how one shale roof behaves worse than the other. Laboratory tests, including point load strength index, slake durability index, moisture activity index, weatherability index, water (moisture) content determination, swelling strain and x-ray diffraction tests were performed to analyze the shale properties. As a result of these tests, strength, durability, water (moisture) content and absorption, weatherability, swelling and mineralogy of weak shales were analyzed. According to these analyses, some useful correlations were found between the engineering properties, moisture-sensitivity indices, and weathering properties of shales. Finally, mine and support design considerations based on the test results were discussed and recommendations to prevent ground control problems were given

Green Remediation of Acid Mine Drainage (AMD)-Impacted Soil and Water

Although mining industries such as coal and minerals generate revenue, they are responsible for a number of negative environmental consequences, and the production of acid mine drainage (AMD) and acid sulfate soil are the most concerning among them. Current AMD management practices are expensive, ineffective, or unsustainable. This study evaluated the potential of a cost-effective and environment-friendly “green” technology in treating AMD-impacted water and soil that utilizes the metal-binding and acid-neutralizing capacity of an industrial by-product, namely drinking-water treatment residuals (WTRs) and the extensive root system of a metal hyper-accumulating, fastgrowing, non-invasive, high biomass perennial grass, vetiver (Chrysopopgon zizanioides L.) to prevent soil erosion. AMD-impacted soil and water were collected from the Tab- Simco mine, an abandoned coal mine in Carbondale, IL. Two locally produced WTRs: Al-WTR and Ca-WTR were used for this study. A field-scale, gravity flow 208L WTRfilter was prepared following the laboratory batch sorption and laboratory-scale WTRfilter column experiments. A 1:6 sand-WTR ratio with a 1:1 Al-WTR and Ca-WTR was optimized for the filter media. The results showed that pH of AMD-water was increased from 2.27 to 7.8, and the concentration of Fe, Al, Zn, As, Pb, and Mn was decreased by 99% after the filtration. Different WTR application rates (2.5%, 5%, and 10% w/w) were tested during a 60 days soil incubation study. A follow-up four-month long greenhouse column study was performed using 5% and 10% w/w WTR application rates. Vetiver grass was grown on the soil-WTR mixed media. Turbidity and Total Suspended Solids (TSS) analysis of leachates showed that soil erosion decreased in the soil-WTR-vetiver system over time. Finally, a scaled-up simulated field study was performed using a 5% WTR application rate and Vetiver for four months. Soil pH increased from 2.6 to 7.7, and soil erosion indicators such as turbidity (99%) and TSS (95%) in leachates were significantly reduced. Results from the study showed that this “green,” inexpensive, and sustainable remediation technique has the potential to effectively treat AMD–impacted water and soil

Моделирование формирования мульды сдвижения земной поверхности над движущимся очистным забоем

За результатами натурних інструментальних спостережень розроблена просторово-часова модель формування мульди зрушення для умов вугільних шахт Західного Донбасу. Запропоновано новий тип ізоліній, що характеризують час і місце виникнення у мульді осідань певної величини.The surface subsidence in Western Donbas coal mines is analyzed. A spatial-temporal model of earth's surface subsidence is developed. A new type of contour - chronoisosubsidence is proposed. These lines characterize the time and place where the certain subsidences are formed