scholarly journals Engineering performance’s evaluation of integrated backfill materials

2021 ◽  
Vol 865 (1) ◽  
pp. 012042
Author(s):  
Xiang Fan ◽  
Jinyang Du ◽  
Facheng Yi ◽  
Yangjie Feng
Keyword(s):  
Backfill Materials

Diffusion of Radionuclides in Brine-Saturated Backfill Barrier Materials

1982 ◽  
Vol 15 ◽  
Author(s):  
E. J. Nowak
Keyword(s):  
Sodium Titanate ◽  
Distribution Coefficients ◽  
Barrier Materials ◽  
Compacted Bentonite ◽  
Metal Diffusion ◽  
Diffusion Cells ◽  
Linear Sorption ◽  
Backfill Materials ◽  
Cylindrical Diffusion ◽  
Apparent Distribution

ABSTRACTThe diffusion of cesium(I), strontium(II), pertechnetate and europium in brine-saturated backfill materials was measured. Plastic diffusion cells containing cylindrical diffusion columns were used for low density backfill materials. The diffusion of gamma-emitters was followed by a gamma scanning technique. Metal diffusion cells constructed entirely from Hastelloy C-276 were used for the diffusion of pertechnetate in highly compacted bentonite. Apparent distribution coefficients calculated from diffusion data are (a) 0.02 m3 /kg for cesium(I) in 40 wt.% mordenite and 60 wt.% bentonite; (b) 0.04 m3/kg for strontium(II) in 10 wt.% sodium titanate and 90 wt.% bentonite; (c) 0.5 m3/kg for pertechnetate in 70 wt.% charcoal and 30 wt.% bentonite; and (d) 3 m3/kg for europium in 100% bentonite. Backfill effectiveness estimates based on batch sorption measurements were supported by these results;however, the diffusion results for europium did not agree well with a model for diffusion retarded by linear sorption. First measurements of pertechnetate diffusion in highly compacted bentonite suggest that anion exclusion may play a role in reducing mass transport rates of anions in this material. Needs for diffusion measurements that take into account site-specific materials interactions are described.

Experiments and Optimization of Mix Proportions for Cement Paste Backfill Materials with Extra-Fine Unclassified Tailings

2017 ◽  
Vol 744 ◽  
pp. 146-151
Author(s):  
Ming Qing Huang ◽  
Xiao Hui Liu ◽  
Hai Yong Cheng
Keyword(s):  
Cement Paste ◽  
Mass Concentration ◽  
Influential Factors ◽  
Range Analysis ◽  
Bleeding Rate ◽  
Orthogonal Experiments ◽  
Optimal Mix ◽  
Backfill Materials ◽  
Unclassified Tailings ◽  
Paste Backfill

To produce effective cement paste backfill materials at iron mines technologically and economically, orthogonal experiments of mix proportions with extra-fine unclassified tailings were carried out. The results of the range analysis showed that the sensitivity of influential factors to the slurry slump is sequentially mass concentration, tailing/rock ratio, and cement/(tailing+rock) ratio. The sensitivity to bleeding rate, concretion time and 28-day uniaxial compressive strength is sequentially mass concentration, cement/(tailing+rock) ratio and tailing/rock ratio. Relationships of paste properties and influential factors can be demonstrated with regression analysis. Additionally, the optimal mix proportion for cement paste backfill was obtained with 78% mass concentration, 7:3 tailing/rock ratio and 1:25 cement/(tailing+rock) ratio. The slump, bleeding rate, concretion time and R28 of the optimal mixture are 25.2 cm, 8.77%, 20.9 h and 1.29 MPa, respectively. The experimental results show a feasible way to produce the industry standard backfilling materials.

scholarly journals Fly Ash Modified Coalmine Solid Wastes for Stabilization of Trace Metals in Mining Damaged Land Reclamation: A Case Study in Xuzhou Coalmine Area

2018 ◽  
Vol 15 (10) ◽  
pp. 2317 ◽  
Author(s):  
Jiu Huang ◽  
Peng Wang ◽  
Chaorong Xu ◽  
Zhuangzhuang Zhu
Keyword(s):  
Fly Ash ◽  
Trace Metal ◽  
Soil Layer ◽  
Fly Ashes ◽  
Migration Ability ◽  
Metal Elements ◽  
Trace Metal Elements ◽  
Simulated Precipitation ◽  
Backfill Materials

In China, coalmine wastes, such as gangues, are used for reclamation of mining subsided land. However, as waste rocks, gangues contain several trace metal elements, which could be released under natural weathering and hydrodynamic leaching effects and then migrate into the reclamed soil layer. However, it is very difficult to find adequate other backfill materials for substitution of gangues. In this paper, we present a novel method and case study to restrict the migration ability of trace metal elements in gangues by using another kind of coalmine solid waste—fly ashes from coal combustion. In this study, fly ashes were mixed with gangues in different mass proportions 1:0.2, 1:0.4, 1:0.6 and 1:0.8 as new designed backfill materials. Due to the help of fly ash, the occurrence states of studied trace metal elements were greatly changed, and their releasing and migration ability under hydrodynamic leaching effect were also significantly restricted. In this research seven trace metal elements in gangues Cu, Zn, Pb, Cd, Cr, Mn and Ni were studied by using soil column hydrodynamical leaching method and simulated precipitation for one year. The results show that under the driving of natural precipitation trace metal elements were generally transported deep inside the reconstructed land base, i.e., far away from soil layer and most of the trace metal elements were transformed into a bonded state, or combined in inert occurrence states, especially the residual state. With this method, the migration activities of tested trace metal elements were greatly restricted and the environmental potential risk could be significantly reduced.

scholarly journals Utilization of Electroplating Sludge as Subgrade Backfill Materials: Mechanical and Environmental Risk Evaluation

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Yu Zhang ◽  
Peixin Shi ◽  
Lijuan Chen ◽  
Qiang Tang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Content ◽  
Environmental Risk ◽  
Coal Fly Ash ◽  
Surrounding Environment ◽  
Electroplating Sludge ◽  
Backfill Materials ◽  
Standard Limit ◽  
The Impact

The electroplating sludge may pose serious threat to human health and surrounding environment without safe treatment. This paper investigated the feasibility of using electroplating sludge as subgrade backfill materials, by evaluating the mechanical properties and environmental risk of the cement-coal fly ash solidified sludge. In this study, Portland cement and coal fly ash are used to solidify/stabilize the sludge. After curing for 7, 14, and 28 days, the stabilization/solidification sludge specimens were subject to a series of mechanical, leaching, and microcosmic tests. It was found that the compressive strength increased with the increase of cement content, curing time, and the cement replacement by coal fly ash besides water content. Among these factors, the impact of water content on the compressive strength is most noticeable. It was observed that the compressive strength declined by 87.1% when the water content increased from 0% to 10%. Besides, leaching tests showed that the amount of leaching heavy metals were under the standard limit. These results demonstrated utilization of electroplating sludge in subgrade backfill material may provide an alternative for the treatment of electroplating sludge.

scholarly journals Stabilizing the Excavation Materials to be used in Fill Layers

2018 ◽  
Vol 4 (5) ◽  
pp. 1165
Author(s):  
Ali Sabbagh Moghadam ◽  
Navid Hadiani
Keyword(s):  
Environmental Issues ◽  
Focus Of Attention ◽  
Waste Materials ◽  
Large Cities ◽  
Backfill Materials ◽  
Execution Order

Daily increase in the amounts of soil and wastes produced by excavation and demolishing of the old buildings in the urban worn out textures has caused great problems in large cities. The environmental issues due to the irrelevant and non-technical disposal of waste materials have attracted attention of researchers with the aim of recycling and use of these materials in the civil and construction activities. Old buildings constitute a significant portion of Sharestan Razavi Blvd in Mashhad which after demolishing of these buildings the area in this section is covered by the backfill materials and those remained from the demolishing of the buildings. In this research, maximizing use of the available materials and minimizing the transportation work as an execution order have been under focus of attention.  Also through performing various tests, the  possibility of recycling, stabilizing and implementing these materials at underlying layers of Sharestan Razavi Blvd has been evaluated and the results are presented.

scholarly journals Physical Modeling of the Controlled Water-Flowing Fracture Development during Short-Wall Block Backfill Mining

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 4) ◽  
Author(s):  
Yun Zhang ◽  
Yongzi Liu ◽  
Xingping Lai ◽  
Jianming Gao
Keyword(s):  
Coal Pillar ◽  
Similarity Criterion ◽  
Test Results ◽  
Control Effect ◽  
Physical Similarity ◽  
Wall Block ◽  
Fracture Development ◽  
Backfill Mining ◽  
Backfill Materials ◽  
Overlying Strata

Abstract Short-wall block backfill mining (SBBM) technology is an effective method to solve the environmental problems in the mining process. Based on the technical characteristics of SBBM technology and the physical similarity criterion, the physical similarity models for comparing the control effects of water-flowing fracture (WFF) development using short-wall block cave mining (SBCM) and SBBM were established, and the deformation and the WFF development of overlying strata above gob were monitored. The test results determined that the composite materials of 5 mm thick pearl sponge+5 mm thick sponge+10 mm thick paper+6 mm thick board were adopted as the similar backfill materials by comparing the stress-strain curves between the similar backfill materials and the original gangue sample. When the backfilling body was filled into the gob, it would be the permanent bearing body, which bore the load of the overlying strata accompanied with the protective coal pillar. At the same time, the backfilling body also filled the collapse space of overlying strata, which was equivalent to reduce the mining height, and effectively reduced the subsidence and failure height of the overlying strata. Compared with SBCM, the test results showed that the maximum vertical deformation, the height of water-flowing fractured zone, and activity range of overlying strata using SBBM were reduced by 91.4%, 82.5%, and 64.9%, respectively. SBBM had a significant control effect on strata damage and WFF development, which could realize the purpose of water resource protection in coal mines.

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