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Investigation on the long-term stability of gas storage in Jintan Salt Mine
Published in Manfred Wallner, Karl-Heinz Lux, Wolfgang Minkley, H. Reginald Hardy, The Mechanical Behavior of Salt – Understanding of THMC Processes in Salt, 2017
X.Y. Yin, C.H. Yang, Y.P. Li, J.W. Chen
According to the borehole data, the rock salt distribution of Jintan Salt Mine is comparatively steady and gentle. As a whole the rock salt layer inclines to north- west and the dip angle is less than 10°. The rock salt body occupies an area of 12 km in the long axis and 5.6 km in the short axis. Its thickness varies from 67.85 m to 230.95 m. The central part of the rock salt body is thicker than the outer. The depth of the top surface of rock salt layers is 850 m to 1100 m. The longitudinal section configuration is relatively simple. From bottom to top, the rock salt bed is composed of three main salt mine layers, layer I, layer II and layer III. The average thickness of layer I is 58 m. The second rock salt layer distributes uniformly with a thickness between 50 m and 80 m (the average thickness is 64 m). The thickness of the third rock salt layer is only 30 m to 50 m. It should be noted that there are two obvious mud rock interlayers: one between layer I and layer II, and the other between layer II and layer III. The thickness of the interlayer between layer I and layer II varies from 0.6 m to 4.9 m (the mean thickness is 3 m), and the thickness of the other interlayer varies from 0.3 m to 4.8 m (the mean thickness is 2.5 m). The rock layers above and below the rock salt layer are mainly composed of mudstone containing rock salt and mudstone.
Faulting structures
Published in M.L. Jeremic, Rock Mechanics in Salt Mining, 2020
The structural mechanics of the crushed breccia of the rock salt dome at the Pride rock salt mine (Romania) also has been studied (Figure 3.3.3). The development of the wide breccia zones up to several hundreds of meters in thickness and its location around the periphery of the salt dome indicate the development of a very strong shear stress in the direction of displacement and a very weak normal stress during salt dome uplift. The tectonic breccia of the rock salt domes of the Carpathian evaporite province consists of 30–60% rock salt; typically it occurs in smaller or bigger transparent cubical crystals cemented by clay/silt material.6
Environmental Applications of Borehole Geophysics
Published in W. Scott Keys, in Environmental Investigations, 2017
Williams (1996) describes the effectiveness of borehole geophysics in obtaining data on the hydrogeology at the site of the Retsof salt-mine collapse in New York. The collapse of two sections of this 10-square-mile mine allowed groundwater to flow into the dry workings at about 15,000 gallons per minute (945 liters per second). The mine workings are located below about 500 ft (152 m) of alluvium and about 600 ft (183 m) of bedrock. Gamma logs at the site enabled identification and correlation of lithologic units within the alluvium and glaciolacustrine sediments above bedrock. Fine-grained glaciolacustrine sediments impeded downward flow of surface water and groundwater into the collapse area. Collapse-related drawdown in the deeper, coarser-grained sediments was about 300 ft (91 m). Within the bedrock limestone, dolomite, shale, and a unit with evaporites were clearly distinguished on gamma logs. These logs indicated that lower resistivity on induction logs was probably caused by an increase in the conductivity of the groundwater, or in the porosity of dolomite, rather than by an increase in clay content. Bedding-plane fractures at the contact between limestone and dolomite were clearly indicated on caliper logs and were identified as zones of saline groundwater flow by impeller flowmeter, temperature, and specific conductance logs. Water levels in wells indicated that collapse-related drawdown in these fracture zones was 500 to 600 ft (152 to 183 m). A caliper log of a well within the collapse area indicated a major fracture zone at the bottom of the well that apparently provided the vertical hydraulic connection between the groundwater system and the mine workings. Williams states that “the hydrogeologic information gained from the borehole-geophysical logging program was critical in evaluating potential remedial actions at the site and developing a plan to assess the effects of the mine collapse on the water resources of the area.”
Evaluation of groundwater quality in district Karak Khyber Pakhtunkhwa, Pakistan
Published in Water Science, 2019
Tehseen Javed, Tahir Sarwar, Ihsan Ullah, Shakeel Ahmad, Sadaf Rashid
The EC ranged from 1210.32 to 3396.15 µS/cm with an average value of 1659.50 µS/cm, and the maximum value was observed in station 15. The spatial distribution of EC is shown in Figure 3. It can be observed that in EC increased from northeast to northwest which indicating the groundwater flow path. The dissimilarity in EC prevailing in this region is mostly credited to geochemical processes, anthropogenic activities and the salt mine in the vicinity. Generally, the EC increased along with groundwater flow because of the effects of topographic conditions, ion exchange and evaporation (Prasanth et al., 2012). The TDS values range from 782.42 to 2167.32 mg/l and with an average of 1532.42 mg/l. EC and TDS showed similar variation (Figure 4). TDS concentration depends on ions types and characteristics, present in the water. Magnesium and calcium are used to classify the suitability of water for drinking and irrigation.
Saving and conserving the caves: reflections on 37 years of listings, disputes, submissions and court cases
Published in Australian Journal of Earth Sciences, 2019
Photo monitoring allows actual impact on the cave contents to be recorded. While photo monitoring has often been discussed, it is rarely implemented. In the Wieliczka Salt Mine in Poland, condensation resolution of salt crystals is monitored by regular macro photography (Urban & Oteska-Budzyn, 2000). Monitoring has shown that the effect of visitors on the atmosphere in show caves is dependent on the volume of the cave, visitor numbers, and visitation intensity. In large caves with reasonable numbers of visitors in well-spaced tour groups, the effect on the cave atmosphere is small and transient whereas in small caves, large visitor numbers in closely spaced tour groups will have a sustained impact on the cave atmosphere, raising the temperature and reducing humidity.
The formation mechanism of irregular salt caverns during solution mining for natural gas storage
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Tianfu Xue, Chunhe Yang, Xilin Shi, Ma Hongling, Yinping Li, Xinbo Ge, Xin Liu
Therefore, in order to avoid or reduce the adverse effects of irregular salt caverns on the safe operation of underground salt cavern gas storage and reduce the number of irregular salt caverns generated in the construction process of the salt cavern gas storage in the future, in this article, combining with the irregular salt cavern cases of Jintan Salt Mine and other areas of the world, the causes of irregular salt cavern shape formation are studied. The factors that lead to irregular salt cavern development can be attributed to three major causes, namely, salt mine geological conditions, salt cavern construction technology and tubing string failures. The research results provide helpful guidance for the future construction of salt caverns to avoid forming irregular ones.