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No description available.

No description available.

In the vicinity of Hoges Store, Giles County, Virginia, certain portions of the Five Oaks and Elway limestones containing more than 97 per cent calcium carbonate crop out near the event of the Thessalia anticline and John's Creek syncline and underlie an extensive area where dips probably are less than 20 degrees. Locally, part of the Benbolt, Gratton, and Witten are also high-calcium limestone. Sites for core drilling and possible subsequent mining or quarrying are inferred from study of exposed rocks, by chemical analyses of channel samples of selected zones of high-calcium limestones and by detailed geologic mapping. The report includes columnar sections showing the character and thickness of the limestone units. One large deposit of chemical-grade limestones was found about 1.5 miles northeast of Hoges Store, which is believed to underlie a large area wherein dips of the mineable strata are less than 15 degree. The amount of recoverable stone is estimated to be 80 million tons. Suggested locations for core drilling are shown. An anticline, two synclines and an intricate structure are the structural features of the area of study. The major structural features of Giles County are delineated on a sketch map. / Master of Science

Based on the results of this investigation certain conclusions were arrived at relative to Portland cement concrete using Dolomitic limestone sand as the fine aggregate. The most important of these are as follows: 1. Fresh concrete continues to gain strength while in the frozen state. 2. Freezing and then thawing of fresh concrete does not have an appreciable effect on the twenty-eight day ultimate strength, and the concrete, if given time to recover, will compare favorably with concrete cured under normal conditions. 3. Freezing of concrete immediately after pouring has a greater effect on the twenty-eight day ultimate strength of the concrete than has freezing for the same period at a more advanced age within the twenty-eight days. 4. Concrete cured at 65°C. tends to increase its twenty-eight day ultimate strength, providing the water lost through evaporation is replaced. 5. High early strength concrete can be obtained by curing ordinary Portland cement concrete at high temperatures. Based on the results of compression tests performed in this investigation, Dolomitic limestone sand has been found to be satisfactory as the fine aggregate for Portland cement concrete; verifying what Messrs. Broyles and Brown had said in 1936 and 1937 respectively. What has been done in the way of concrete research at Virginia Polytechnic Institute is satisfactory for relatively new concrete using Dolomitic limestone sand as the fine aggregate; but it is wondered how this concrete will stand up over a long period of time. Professor Hartman and Dr. Holden have inaugurated some long time studies at the Institution, but there is still much room for further investigation. Dolomitic limestone rock has proven itself worthy when used as the coarse aggregate for Portland cement concrete. It is up to time and future research to prove the worth of its sand used as the fine aggregate. / Master of Science

Neutralization by limestone is a common treatment for acid mine drainage (AMD). The effectiveness of using limestone to treat AMD can be reduced by aluminum (Al) and iron (Fe) oxyhydroxide coatings that form on the limestone, because the coatings inhibit the transport, and thus neutralization, of hydrogen ions (H+) derived from acid mine drainage. I used mixed flow reactor experiments to investigate the effect of Al coatings on the diffusion of H+ to the surface of limestone and to quantify how those Al coatings affect the limestone dissolution rate. Experiments used acidic Al sulfate solutions with initial Al concentrations ranging from 0.002 M to 0.01 M (32 to 329 ppm) and pH values ranging from 3.7 to 4.2, which are typical of conditions found at AMD sites. Cleaved pieces of Iceland spar calcite were used as a proxy for limestone. The pH was measured in the effluent to determine the rate of H+ consumption. Effluent solutions were analyzed for Al, calcium (Ca) and sulfur (S) using inductively coupled plasma optical emission spectroscopy (ICP OES). Examination of the precipitated coatings using x-ray diffraction indicated that amorphous poorly crystalline gibbsite is the primary Al coating but scanning electron microscope analysis also suggests the possible presence of a poorly crystalline sulfur containing phase, such as hydrobasaluminite. The experimental data were used to calculate the diffusion coefficient of H+ through the Al coatings. The calculated diffusion coefficient for H+, assuming a gibbsite and/or hydrobasaluminite layer, ranged between 10-13 to 10-11 m2/sec, that are significantly lower than in pure water. / Master of Science

Successive Alkalinity-Producing Systems (SAPS) have proven to be a viable alternative to chemical treatment for renovating acidic mine drainage (AMD). The lack of water quality based design guidelines, however, is believed to be a cause of the variability of SAPS performance in the field. This study monitored eight SAPS systems for the purpose of determining the effect of influent water quality and system design on system performance. Monthly water quality data were obtained for each system over periods ranging from 3 to 5 years. All systems demonstrated an ability to generate alkalinity and/or neutralize acidity. These systems revealed significant correlations between net alkalinity production and log residence time (r = 0.7414), influent total iron (r = 0.7357), and influent non-manganese acidity (r = 0.6919). From these relationships, a calibrated model was developed for predicting SAPS net alkalinity generation. As a compliment to the field study, a series of laboratory-scale SAPS columns were studied for a period of 12 months to examine the effect of residence time on system performance and to monitor the internal changes in water quality. The columns were operated at residence times of 17, 30, 60 hours with three replicates each and were subject to ambient temperature fluctuations. Data revealed that systems with residence times below 25 hours in the organic layer were unable to adequately reduce dissolved oxygen concentrations in the organic layer to prevent limestone armoring. The results of this study suggest water quality based guidelines for designing SAPS systems. / Master of Science

M.S.

The Mississippian Newman Limestone (0-30 m thick) in eastern Kentucky contains pink-staining, aquifer-related cements (up to 750 ppm Mn+2); up to 1000 ppm Fe+2; δ¹⁸ -7.5 to -6.8 per mil; δ¹³C 1.7 to -6.8) that is non-luminescent (low Fe and Mn) in the recharge area, but becomes uniformly dully luminescent downdip. This aquifer developed toward the end of Newman limestone deposition during two major regressions (Late Mississippian and Mississippian-Pennsylvanian time). Shallow burial cementation was less common to the south-east into the Appalachian Basin, where the Mississippian limestone is up to 1000 m thick. Here, phreatic meteoric diagenesis in more distal parts of the aquifer caused high-Mg calcite and aragonite grains to be leached, while isotopically light, fine dolomite (δ¹⁸O -1.7 to -6.7 per mil; δ¹³C 2.7 to -5.3 per mil) replaced muddy carbonates in a paleomixing zone. As the aquifer evolved, low-iron, dully luminescent calcite was precipitated from reducing pore waters. With increasing burial, compaction caused spalling of ooid cortices; iron rich saddle dolomite (δ¹⁸O -5.5 to -11.2 per mil; δ¹³C 0.9 to 1.4 per mil), and moderately ferroan (purple-staining) calcite cement (0-1200 ppm Mn2+; 1000-3000 ppm Fe2+; δ¹⁸O -4.6 to -10.6 per mil; δ¹³C 2.7 to -6 per mil) precipitated in pores and fractures from waters that were increasingly dominated by warm, basinal, oil-bearing fluids expelled from dewatering Paleozoic shales. These coarse dolomites overgrew early fine dolomite of reservoirs, while the purple staining calcite filled intercrystal porosity outside of the reservoirs. At or near deepest burial, Fe-rich (blue-staining) calcite (up to 1200 ppm Mn2+; 3000-7000 ppm Fe2+; δ¹⁸O -3. 8 to -7. 8 per mil; δ¹³C 1. 8 to -1. 5 per mil) precipitated in much of the remaining void space in the limestones. During uplift of the sequence late calcite cements with decreasing Fe contents were precipitated from increasingly oxidizing fluids that penetrated the section through fractures and remaining pore spaces. / M.S.

Two gigantic landslides in carbonate sequences were studied through a combination of remotely sensed datasets and detailed field investigation. Field investigations supplemented the remote analysis at both sites. The work presents the first detailed documentation of the Seymareh (Saidmarreh) landslide, Zagros Mountains, Iran, which is shown to be the largest known rock avalanche in the world and the largest known landslide of any type on the Earth’s land surface. Volume of the Seymareh rock avalanche (38 Gm³) was previously underestimated by nearly 50 percent. The failure mode was complex planar sliding involving fold-related bedding-parallel shears and local break-through of bedding. The overall dip of the sliding surface was 11°. Lateral release and toe release were provided by tectonically-weakened joints and by break-out likely assisted by fluvial undercutting, respectively. Broad scar morphology and outcrop-scale features indicate the presence of nine discrete sliding surfaces distributed through the failed sequence and define nine stacked plates involved in the detachment. The Valley of the Rocks rock avalanche (1.3 Gm³), Rocky Mountains, Canada is described in detail for the first time and shown to be the largest known rock avalanche in North America as well as the largest known landslide of any type in Canada. The failure mode was simple planar sliding along a bedding-parallel, slightly concave-up surface possibly coinciding with a thrust fault (average dip 25°). Lateral release and toe release were provided by bedding-normal joints and by glacial undercutting, respectively. There is a surprisingly high degree of similarity between the two rock avalanches, despite differences in tectonic and climatic setting.. Similarities and differences between the two gigantic landslides suggest several factors important in volume determination of gigantic landslides in carbonate sequences: 1) extensive contiguous source slope; 2) high degree of structural continuity, especially across slope parallel to strike; 3) a comparatively low failure surface dip; 4) discontinuity-parallel slopes, and subsequent toe undercutting; and 5) hard-over-soft geomechanical contrasts. Comparison with magnitude-mobility relationships for landslides over five orders of magnitude shows that the Seymareh rock avalanche suggests an upper limit for landslide mobility (fahrböschung = ~4°) on the Earth’s continental surface.