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This study investigates clayey soil from a road project situated in the district of Lodhran, Punjab, Pakistan. The subgrade prepared with the soil distorted due to heaving after a certain period of its construction. First, laboratory tests were conducted to explore the reason for this problem, examining the fundamental engineering properties of soil. The test results show that the soil acts as a soft material when water content reaches 30%, significantly reducing its strength. The soft soil is generally considered unsuitable for civil work due to its poor performance behaviour. So, the performance of clayey soil was examined in the study at its soft state by coupling it with stronger materials, such as polyethylene polymeric reinforcement and sand, developing laboratory-scale foundation models. Based on the model studies, the study proposes a sustainable polyethylene–sand–soft soil model, which shows 155 and 56% higher ultimate bearing capacity (BC) than soft soil and sand-reinforced soft soil foundations. The changes in BC occur due to the reinforcement action of the polyethylene reinforcement, which is associated with its tensile membrane action effects and interlock bonding at the soil-reinforcement interface. Practically, the study can reduce the dependency of industry practitioners on sand materials. Using polyethylene in civil work is viable for environmental sustainability. [ABSTRACT FROM AUTHOR]

The 3D sand printing (3DSP) technology provides a richer realization path for the sustainable development of the manufacturing industry. It has the advantages of one-time molding, reducing design constraints and machining amount, and easy control of casting dimensional accuracy. Therefore, studying the impact of process parameters of the printing process on printing efficiency, resource consumption, and carbon emissions is the basis for the sustainable development of 3DSP technology. In this paper, starting from the main influencing parameters such as printing layer thickness, recoater speed, printing angle, and single printing quantity, a relationship model between printing parameters and carbon emission sources is constructed. A total factor carbon emission prediction model of 3DSP process including the impact of capital and labor is established. Build an influence relationship with printing parameters as independent variables and carbon emissions as dependent variables. Taking the sand casting industry as an example to verify the above model, the experimental results show that the thickness of the printing layer has the greatest impact on carbon emissions. When the layer thickness is 0.36 mm, the speed of the recoater is 0.22 m/s, the printing angle is (0°, 0°, 90°), and the single print quantity is 84, the total carbon emission is the lowest and 28.77% less compared to the parameter with the highest carbon emission. The average relative error of the predictive model is 1.929%. The results of this study can provide some new ideas for sustainable development of additive manufacturing technology. [ABSTRACT FROM AUTHOR]

The economic viability of sand in the construction industry depends on its size, shape, shell content, etc. It is imperative to understand the proportions of sand subclasses and shell content in sand sediment while planning exploration and mining. The existing sediment classifications (Particle Size Distribution Classifications) based on Sand‐Silt‐Clay (SSC) or Gravel‐Sand‐Mud (GSM) of different authors have not addressed these issues and it remains as a gap area till now. Hence, a new physicochemical classification ("Sand Types") of sand that falls in the "sand fields" of SSC plots pertaining to two famous authors is being proposed. The freeware program "Sand Types" developed for plotting types of sand in the ternary diagram helps to plot the data in a triangular diagram and identify their physicochemical properties. The program also offers conditional strings that are prepared based on the proposed classification and are coupled with that of SSC classifications. These conditional strings work in ArcGIS10.x platform for the preparation of sediment distribution maps with meaningful information. This would enable construction industry/end‐users to plan and execute detailed exploration and mining programs at great ease. [ABSTRACT FROM AUTHOR]

The extreme demand for aggregate leads to the exploitation of riverbeds for fine aggregates, affecting the environment adversely. Therefore, a suitable alternative to natural river sand is essentially required. This study focuses on preventing environmental impact by developing polycarboxylate ether (PCE) sand to replace natural river sand (NRS). Development of polycarboxylate ether (PCE) sand by mixing high-volume fly ash, bottom ash, cement, natural river sand, and locally purchased high-solid-content polycarboxylate ether–based superplasticizer (HSPCE). All the physical and chemical properties of PCE sand were observed and satisfied the requirement of current standards. PCE sand yields a good specific gravity of 2.31 and is classified as Zone I sand with a satisfactory friction angle (37°) compared with NRS and geopolymer fly ash sand (GFS). Although the water absorption (6.83%) and pH (12.18) are slightly more than those of GFS and NRS, the alkali silica reaction and soundness are well within the permissible limit as per Indian standards. The chemical analysis by X-ray fluorescence showed the presence of high amounts of SiO2 and Al2O3 with magnitudes of 58.879%, and 26.77%, respectively. Finally, the compressive strength of M25 grade concrete using PCE sand and GFS was observed to be 87.51% and 83.82% with respect to NRS after 28 days, respectively. The results of this study indicate that PCE sand can be a good alternative to NRS for construction work because it not only reduces the environmental effect due to sand mining but also focuses on utilizing fly ash and bottom ash. [ABSTRACT FROM AUTHOR]

As an important ecosystem and valuable natural resources, desert has great potential for industrial development. Exploring the path to realize the value of ecological products in desert areas can stimulate the endogenous driving force of sand industry. This article takes the Ulanbuhe Desert (within Dengkou County) as the research area, constructs an ecological product value realization effectiveness evaluation model based on Gross Ecosystem Product (GEP) accounting, and conducts evaluation research. The results show that the GEP of the County in 2020 is 10.705 billion yuan, which is 1.85 times of the GDP of that year; wind and sand control is the core service function of the ecosystem, accounting for 66.05% of the GEP of that year. From 2010 to 2020, GEP increased by 1.74 times, with the fastest growth rate in ecological and cultural values (182%) and the largest increase in ecological regulation values (3.024 billion yuan); the main driver of the expanding GEP values and scope was the increase in forest and grassland areas in areas such as the Sargent Settlement Sumu. Over the past 10 years, the average values of green gold index (1.77), primary conversion rate of ecological products (23.07%), value of ecological products (21.27%) and value of ecological culture (1.80%) are seriously low, which indicate that the value realization of ecological products needs to be improved. In addition, this article further explores the impact of land use change on the value of ecological products, in order to reveal the root causes of GEP changes, which can effectively protect the ecological environment and achieve coordination between regional economic development and ecological construction. [ABSTRACT FROM AUTHOR]

Fishing and sand mining in Cambodia may not appear to have much in common. However, digging deeper reveals important parallels. Both fishing and sand mining support livelihoods and are connected to a limited natural resource. Meanwhile, they are both typified by precarious livelihoods, on the one hand, and overexploitation, on the other. In bringing these two topics together, the paper combines empirical qualitative research from two separate studies conducted by the co-authors in Cambodia, one in coastal fishing villages and another in the sand mining industry along the Mekong River. We argue that the interplay between fishing and sand mining has paradoxical impacts on livelihoods, supporting one group while undermining another. Using a precarity analysis lens, we show how an unconventional, and largely invisible frontier of natural resource exploitation—sand mining—is intertwined with fisheries, and expands our understanding of the relationship between precarious labour, environmental change, and livelihoods. [ABSTRACT FROM AUTHOR]

By obtaining and studying special‐purpose building materials based on the wastes of various industrial fields it has been found that that they exhibit a complex of predefined properties, and are both hydraulic and air binding materials. Physico‐mechanical properties of such materials vary over a wide range: water‐cement ratio – 0.12 – 0.25; initial set – from 50 minutes to 1 hour 50 minutes, final set – from 2 hours 15 minutes to 3 hours 25 minutes; compressive strength after 3 days of setting – 30 – 60 MPa, compressive strength after 28 days of setting – 50 – 85 MPa. In addition, experimental materials exhibit a complex of special properties: computed mass absorption ratio 200 – 280 cm‐1, sulfate resistance ratio after 6 months of setting in aggressive medium – 1.1 – 1.2. It is possible to obtain the following materials from chemical industry wastes: sand lime bricks (silicon‐containing wastes), heavy fillers for special purpose concretes (chromium wastes), various types of ceramics (calcium‐containing wastes), and in particular ferromagnetic ceramics (barium‐containing wastes). [ABSTRACT FROM AUTHOR]

Aeolian sand (AS) and recycled coarse aggregate (RCA) can be reasonably utilized as green materials for concrete modification. The paucity of natural sand and gravel in the construction industry is anticipated to be remedied by the use of these two eco-friendly concrete ingredients. This is incredibly important for environmental protection. Study on the damage law of self-compacting concrete with the addition of AS and RCA (ARSCC) under severely cold conditions is of great significance for the promotion and implementation of this material. In this study, 12 groups of ARSCC specimens were prepared for freeze–thaw cycle experiments, with AS substitution rates of 0, 20%, 40%, and 60% as well as RCA replacement rates of 0, 25%, and 50%. Then, the degradation mechanism of ARSCC freeze–thaw damage was discussed from both macroscopic and microscopic perspectives via mass loss rate (Wn), relative dynamic modulus of elasticity (Pn), bubble spacing factor, and SEM analysis. Finally, the response surface method was utilized to determine the damage variable. A freeze–thaw damage model for ARSCC was developed based on the Weibull distribution and Grey theories. The results showed that the Pn could reflect the evolution law of the internal structure of ARSCC. Appropriate addition of AS to fill the large, harmful pores in RCA would inhibit freeze–thaw damage of ARSCC. The optimum substitution rates of AS and RCA were determined to be 20–40% and 25–50%, respectively. In addition, the values obtained from theoretical damage modeling and experiments were in good agreement. The acquired damage model had the potential to predict ARSCC damage under freeze–thaw cycles. [ABSTRACT FROM AUTHOR]

Like many other natural resources, sand has become integral to technologies that symbolize modernity and development, but that depend upon an imperative of low cost. In India, sand began to be commoditized in the early twentieth century as an input in a powerful new building technology, reinforced cement concrete (RCC). With the expansion of cities and major infrastructure projects since independence and especially since the 1990s, sand mining has nonetheless remained characterized by small-scale enterprises and small technologies; it is also controlled by regional powerholders who operate on the legal margins, widely referred to as 'sand mafias'. This article draws upon archival and ethnographic research on sand mining for construction in the city region of Bombay/Mumbai to show that the sand mining industry there has effectively come to operate over time through various methods of drawing marginal value from devalued labour techniques and delegitimized or tactical modes of operation. These destructive-productive activities, at a broad level, constitute micro-practices of contemporary capitalism (modes of flexible accumulation) on a resource frontier. But equally, for many of the people involved in them, their value lies in their unpredictable excesses and terrains of resource-making that likewise buoy changes in the technological assemblage. [ABSTRACT FROM AUTHOR]

Occupational exposure to respirable crystalline silica (RCS) is common for several occupations in construction, not only because of its presence in many handling materials but also in processes such as grinding and sawing. This study investigated workplace exposure to RCS as quartz in industries and occupations within road construction in Alberta through the RCS monitoring database provided by the Alberta Roadbuilders and Heavy Construction Association (ARHCA) between 2007 and 2016. Descriptive statistics were calculated for exposure-related variables, and mixed model analysis was performed to determine factors affecting the exposure levels. Results showed that the highest exposed workers were in the sand and gravel industry (GM = 45 μg/m3). For worker occupations, geometric means ranged from 78 μg/m3 for crusher operators to 10 μg/m3 for concrete truck operators. The maximum exposure severity was 33.3 times the occupational exposure limit (OEL) for the sand and gravel and 31 times the OEL for tower operators. The results also showed the effect of seasonal variability on RCS exposure levels. The heterogeneous exposure results indicated significant room for improvement and that controls should focus more on the activity performed than the occupation to lower exposure to RCS levels in industries. [ABSTRACT FROM AUTHOR]

Sand sustains the foundations of modern economies, but almost nothing exists in the way of global sand regulation and governance. Despite the documented risks posed by rampant, unregulated extraction, a global governance regime is unlikely to emerge any time soon. This Comment argues that possible governance solutions will need to come from what we currently have in the legal toolbox. In other words, existing frameworks, principles, and lessons from case law must be drawn upon and refitted to tackle some of the most salient issues caused by sand mining. This Comment aims to illustrate that even a highly fractured legal landscape can still offer invaluable guidance moving forward. To that end, this Comment also explores the first possible steps toward a global governance framework. Specifically, countries should take advantage of lowhanging fruit--easy opportunities to integrate sand into existing frameworks and concepts--in order to patch critical regulatory gaps and establish a foundation for future cooperative efforts. [ABSTRACT FROM AUTHOR]

Sand production is undesirable matters, occurring in wells that are producing from sand reservoirs. It causes many problems such as erosion and grains accumulation in downhole and surface equipment’s, and formation subsidence. Important stage in sanding problem solution is a prediction of likelihood sand production intervals. In present paper, a vertical well X1 that is producing from Asmari reservoir in Y field at southern Iraq was selected for study. Asmari reservoir was classified to six units: A, B1, B2, B3, B4, and C. B zones consisted from sandstone with others rock types. Eight approaches were used for prediction sanding onset intervals by dealing with X1 well as open hole completion. Utilized eight prediction methods are compressional sonic wave (CSW), unconfined compressive strength (UCS), total porosity (PHIT), shear modulus to bulk compressibility (G/Cb), B-Index, Schlumberger index (S- Index), combined index (Ec-Index) and critical drawdown pressure (CDDP). All these methods performed based on 2462 measured points of CSW, sonic shear wave log (SSW), and density log (DL). Sand production likelihood intervals was selected by determination of cutoff values of adopted methods. Sand is possible to occur if interval has values lower than cutoff values of G/Cb, UCS, B-Index, S-Index, Ec, and CDDP and greater than cutoff values of CSW, and PHIT. Obtained cutoff values of eight approaches were 800 x 109 psi2, 36 Mpa, 0.2, 80 us/ft, 10000 Mpa, 108 Mpa, and 2700 Mpa, of G/Cb, UCS, PHIT, CSW, B-Index, S-Index, and Ec respectively. As well as sand production is possible to occur of bottomhole flowing pressure lower than calculated CDDP. Some Intervals had high CDDP that referred to abnormal pressure zones consisted from shale. Determination of sand onset intervals is a key for selecting best methods for controlling. [ABSTRACT FROM AUTHOR]

Manufactured sand is one of the effective ways to alleviate the extreme shortage of natural sand in the construction industry. This paper uses granite and limestone manufactured sand to study the effect of high fines content on the durability of high-strength manufactured sand concrete, and analyzes its influence mechanism by combining macro and micro test methods. The results show that the carbonation depth of manufactured sand concrete is the smallest when the fines content is 10%. When the fines content is less than 15%, the chloride and sulfate impermeability of concrete are improved effectively. Through macroscopic and microscopic tests, it is found that the main reason why fines can improve the durability of concrete is the filling effect. Too much fines will inhibit the hydration of cement and adversely affect the durability of concrete. Therefore, the fines content of high-strength manufactured sand concrete should be controlled within 5~15%, and the durability is the best when the fines content is 10%. [ABSTRACT FROM AUTHOR]

Post-mining soil and solid waste from the silica sand refining industry is widespread and the potential long-term impact of toxic metals and metalloids is a significant and under-appreciated issue. This study presents the characteristics of post-mining soil and solid waste resulting from silica sand purification to observe its physical, chemical, and biological composition. Analysis of the physical properties was carried out with reference to ASTM 112-10 and the results show that post-mining soil contains 36.95% sand, 18.80% clay, and 42.74% silt, with coefficients of permeability and porosity of 0.69×10-6 cm·s-1 and 35.84%, respectively. Meanwhile, the solid waste contains 43.35% sand, 35.96% clay, and 20.68% silt with coefficients of permeability and porosity of 1.49×10-6 cm·s-1 and 51.12%. The overall mineralogy and morphology of both samples showed that they have the same chemical composition as gehlenite (Ca2Al2SiO7), spinel (MgAl2O4), akermanite (Ca2MgSi2O7), monticellite (CaMgSiO4), aluminum oxide (Al2O3), magnetite (Fe3O4), and hematite (Fe2O3) supports this data. The chemical composition of both samples is SiO2, Al2O3, CaO, and MgO, but the post-mining soil has lower heavy metal and nutrient contents compared to solid waste. Meanwhile, solid waste has a high content of heavy metals and nutrients due to washing and bonding from the silica sand purification process. The abundance of bacteria (Colony Forming Unit) for the 10-4 and 10-5 dilutions in post-mining soil was 1.59×10³ and not detected, while in the solid waste, 4.10×105 and 1.64×105 were found, respectively. This study can be used as base values for modifying the two samples, which can be applied in mining land reclamation. [ABSTRACT FROM AUTHOR]

The use of crushed limestone sand in the concrete industry will be quite possible and imperative for environmental reasons. Many researchers around the world have found that concrete based on 50% substitution of river sand by limestone sand gives better physico-mechanical characteristics. The main objective of this investigation is to search for an optimal percentage of silica-limestone fines resulting from the substitution of half in quantity of alluvial sand by crushed limestone sand in ordinary concrete. The proportions of fines that were tested in this work are 6%, 8%, 10%, 12% and 14%. The obtained results revealed that concrete based on silica-limestone sand and containing 14% of the same type of fines strongly improves the different mechanical strengths and participates in the reduction of 10% and 13%, of the coefficient of capillary absorption and of the porosity accessible to water, respectively, compared to the control concrete. In addition, good statistical relationships between the studied parameters were also found. [ABSTRACT FROM AUTHOR]

Starting from the importance of the mining industry and the way the gravel pits negatively influence the protected natural areas, this study focuses on monitoring by satellite remote sensing of the mining perimeters regulated by the environmental protection authority of Sălaj County, as well as on the compliance of the economic agents with the correct exploitation and positioning of the regulated mining perimeters. [ABSTRACT FROM AUTHOR]

There are mainly two different ways of producing sand cores in the industry. The most used is the shooting moulding process. A mixture of sand and binder is injected by compressed air into a cavity (core), where it is then thermally or chemically cured. Another relatively new method of manufacturing cores is the use of 3D printing. The principle is based on the method of local curing of the sand bed. The ability to destroy sand cores after casting can be evaluated by means of tests that are carried out directly on the test core. In most cases, the core is thermally degraded and the mechanical properties before and after thermal exposure are measured. Another possible way to determine the collapsibility of core mixtures can be performed on test castings, where a specific casting is designed for different binder systems. The residual strength is measured by subsequent shake-out or knock-out tests. In this paper, attention will be paid to the collapsibility of core mixtures in aluminium castings. [ABSTRACT FROM AUTHOR]

The global consumption of sand by the concrete industry has increased significantly over the years. Natural sand has become a desired commodity in numerous regions of the world. To protect both the existing resources of natural sand and utilize waste materials, drastic actions are urgently needed. The production of cement mortars, which are solely based on fine aggregate, is responsible for the large consumption of natural sand. In the described research program, we proposed to substitute 50 % of the natural sand in mortars with fly ash and slag. The strength properties and durability characteristics of the new mortars were tested. It was proved that mortars with fly ash and slag can be used for specific applications in civil engineering. Areas for future research associated with the mortars in question were also pointed out. [ABSTRACT FROM AUTHOR]

Reducing waste disposal from stoneware industry and reducing use of sand in construction industry are both important for sustainable development. One strategy to tackle both problems is to utilize the waste from stoneware factories to replace the sand in mortar/concrete production. To study the possible use of granite polishing waste (GPW) as sand replacement, a research programme was launched to test the flowability, cohesiveness, adhesiveness, strength and sorptivity of mortar mixes made with various GPW contents and water/cement ratios. To investigate the fundamental causes of the effects exerted by the GPW, the packing density, water film thickness and porosity of the mortar mixes were also measured. The results showed that adding a suitable amount of GPW as sand replacement would, apart from reducing waste disposal and sand consumption, also improve mortar performance by filling the voids between sand particles to decrease the voids ratio and porosity and increase the packing density and water film thickness. Overall, within the ranges of mix parameters covered in this study, the addition of GPW to replace 15% to 20% sand by volume would increase the strength by 31.2% to 70.9% and improve the rheology and impermeability. Unlabelled Image • Use of granite polishing waste (GPW) as sand replacement in mortar is proposed. • This can reduce consumption of natural sand and disposal of stone dust waste. • Packing density of particles and rheology of fresh mortar would be increased. • Moreover, strength and impermeability of hardened mortar would be increased. • The optimum replacement ratio of sand by GPW is about 15% to 25%. [ABSTRACT FROM AUTHOR]

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Abstract: The scope of the research was to assess and evaluate the phase composition of different kinds of kaolinitic sand in Sinai, Egypt, and its possible applications in ceramic industries. For this purpose, four samples of kaolinitic sand were mechanically dry and wet sieved, and the percentages passing through sieves sizes of different sizes for each sample were calculated. Chemical and mineral investigations, as well determining their stoichiometric phase composition, were carried out on the raw samples as well as the ones fired at 1200 and 1400°C, respectively. It was concluded that these samples could be used as aluminium silicate concretes and bricks for lining of different types of furnaces after firing at temperatures > 1550°C. [ABSTRACT FROM AUTHOR]

Background and Objective: Non-biodegradation in nature and creation of adverse health effects in humans is important features of heavy metals. The main objective of this study was to determine the level of contamination, carcinogenic and non-carcinogenic risks of falling dust containing heavy metals on residents around the industrial areas of Ardakan. Another objective was to identify potential sources of heavy metal release into the environment. Materials and Methods: In this cross-sectional analytical study, the falling dust was collected in summer around Tile and Ceramic, Khak-e-chini, sand and gravel and glass industries by installing 35 Inverted Frisbee traps with artificial grass cover. The concentration of Cd, Ba, Cu, Ni, Cr, Mn and V were measured by ICP-MS. Probable sources of the heavy metal of the dust were evaluated using Pearson correlation coefficient and cluster analysis. Ecological risk indices for determining the level of contamination and proposed relationships proposed by the US Environmental Protection Agency were used to assess the carcinogenic and non-carcinogenic risks. Results: The highest and lowest mean concentrations of heavy metals were measured for Cd and Ba, respectively. The results of Pearson correlation analysis and cluster analysis revealed three anthropogenic and also natural sources for heavy metals of the falling dust. According to the Ecological Risk Potential Index, Cd in 45.10% of the samples was in a very high class and in 54.88% of the samples was a high class. Pollution class of the ecological risk index of all the heavy metals was medium to high. The carcinogenic risk of Cr and Ba in children and adults was estimated to be higher than 10–4. In both age groups, the Hazard index for each metal was less than 1 and its sum was measured as 1.29 for children and 0.16 for adults. Conclusion: Cd increases the ecological risk of the falling dust in the area. Ther heavy metal carcinogenic risk results showed that the concentrations of Cr and Ba were higher than standard. Also, the non-carcinogenic risk was higher in children than in adults. [ABSTRACT FROM AUTHOR]

• We evaluated the burden associated with nonfatal slip, trip, and fall incidents. • The focus of the work was surface stone, sand, and gravel mines in the U.S. • The incidence rate was 62 per 10,000 full-time equivalent employees per year. • Incidents led to approximately 23,800 total days lost per year. • The estimated cost of the incidents was approximately $17.5 million per year. • In addition, assessed violations cost the industry approximately $3 million per year. Slips, trips, and falls (STFs) pose a significant financial burden to employers and account for over 33% of the total nonfatal workers' compensation cost in the United States. Previous analyses documenting the burden of STF incidents in the mining industry have focused on occupational fatalities or STFs during equipment ingress, egress. There is limited information on the burden of nonfatal STF incidents in the mining industry and most of it is outdated. Hence, to increase awareness and highlight the importance of STFs in the mining industry, this analysis documents the burden associated with nonfatal STF incidents at surface stone, sand, and gravel (SSG) mines from 2008 through 2017. In this time frame, nonfatal STF incidents occurred at a rate of 62 per 10,000 full-time equivalent (FTE) employees per year. Pits had a higher prevalence of injuries, but plants had a higher incidence rate. In addition, nonfatal STF incidents at surface SSG mines led to approximately 23,800 total days lost per year with an estimated cost to the mining industry of $17.5 million per year. Assessed violations that are not related to reported injuries but are related to STF hazards identified during Mine Safety and Health Administration (MSHA) inspections cost the mining industry approximately $3 million per year from 2013 through 2017. Based on the data analyzed in this study, falls to the lower level pose a higher burden in terms of cost; however, falls to the same level have a higher number of incidents and incidence rate. [ABSTRACT FROM AUTHOR]

Purpose: To support the needs of downstream users of zircon sand and other industry stakeholders, the Zircon Industry Association (ZIA) conducted an industry-wide life cycle assessment (LCA) with the aim to quantify the potential environmental impacts of zircon sand production, from mining to the separation of zircon sand (zirconium silicate or ZrSiO4). This novel work presents the first, globally representative LCA dataset using primary data from industry. The study conforms to relevant ISO standards and is backed up by an independent critical review. Methods: Data from ZIA member companies representing 10 sites for the reference year 2015 were collected. In total, more than 77% of global zircon sand production was covered in this study. All relevant mining routes (i.e. wet and dry mining) were considered in the investigation, as well as all major concentration and separation plants in major zircon sand–producing regions of the world (i.e. Australia, South Africa, Kenya, Senegal and the USA). As it is common practise in the metal and mining industry, mass allocations were applied with regard to by-products (Santero and Hendry, Int J Life Cycle Assess 21:1543–1553, Santero and Hendry 2016) where economic allocation is only applied if high-valued metals like PGMs are separated with a process flow. A sensitivity analysis was used to understand the relevance of the major contributing effect of the life cycle impact assessment (LCIA) results, power consumption. Results and discussion: It was shown that mining is the main contributor to all impact categories (between 65 and 90% compared with the mineral separation plant). For example, primary energy demand (PED) and global warming potential (GWP) contribute 76% and 70%, respectively, to the production of 1 kg of zircon sand. PED for 1 kg of zircon sand is calculated to be 4 MJ, whereas the GWP is 0.32 kg CO2 equivalent per kg of zircon sand. The main influencing factor in the mining process is electricity consumption. Conclusions: In conformity with relevant ISO standards, and backed up by a critical review, this LCA quantified the potential environmental impacts associated with the production of the zircon sand (ZrSiO4). With this study, a sound dataset for downstream users of zircon sand has been provided. It is the first LCA dataset of the ZIA. [ABSTRACT FROM AUTHOR]

Abstract Changes in effective stress around a borehole due to pressure drop can cause formation instabilities leading to issues such as sand/solid production and wellbore stability. Analytical studies have been conducted in the past to gain insights into physical mechanisms involved in this complex process. The developed analytical solutions for such hydro-mechanical instability often consider perfectly plastic behaviour for the rock, whereas the field observations suggest strong strain softening as a result of pore pressure drop. In addition, these analytical solutions are not verified with experimental data in many instances. In this study, we developed a series of closed form solutions to predict the stress and strain changes around a borehole within poro-elasto-softening-plastic concept using Mohr Coulomb failure criterion. For the purpose of describing the pore pressure induced softening behaviour; an exponential function was used to relate the evolution of yield surface to plastic shear strain. In a further step, a series of hollow cylinder experiments were conducted on sandstone samples where different hydrostatic confinements at elevated pore pressures were applied. The hollow cylindrical samples were imaged before and after the experiments using 3D X-ray micro Computed Tomography technique (micro-CT) to precisely identify the collapsed-damaged and plastic zones formed around the borehole. Finally, the results from the experiments and micro-CT analysis were compared with the model prediction and a good agreement was observed. [ABSTRACT FROM AUTHOR]

Previous studies show that the control of geological structure on gas and water distribution is extremely negative or even can be ignored in Ordos Basin. However, it is found that the structural trap has obvious control effect on the distribution of gas and water, especially in Shan23 sub-member in Wushenzhao. The characteristics of reservoir, trap types and accumulation rule of gas reservoir are discussed in this paper, and the results show that Shan23 sub-member belongs to extra-low porosity and extra-low permeability and even ultra-low permeability reservoirs. The type of gas reservoir trap is a structural-lithologic trap with a quasi-domed shape. The accumulation and preservation of natural gas are controlled by both low-amplitude structures and sand bodies. [ABSTRACT FROM AUTHOR]

Sand production while producing hydrocarbons from a well is a critical issue faced by the oil and gas industry. It is a complex process controlled by several factors, including the mechanical failure of materials around the wellbore and the material erosion due to fluid flow. The coupling between these factors leads to considerable challenges in modeling and predicting sand production. This paper presents a finite element based approach for simulating the realistic sanding process, considering coupling between mechanical failure and hydrodynamic erosion of the rock. A well calibrated sand criterion proposed by Papamichos was implemented to model sand erosion. An adaptive meshing technique was used to track receding of the eroded surfaces and to progressively modify boundary conditions on new surfaces, which are important for capturing the realistic sanding process. Sand production in both open-hole and perforated-casing completions was simulated to illustrate capabilities of presented method. Numerical results show that sand production is controlled primarily by the plastic strain and flow velocity around the wellbore. Other parameters, including drawdown, in-situ stress, and perforation orientation, are shown to have considerable influence on sand production rate and are discussed in this paper. [ABSTRACT FROM AUTHOR]

The article questions whether the qualitative differences between frac sand and common building sand could lead courts to conclude that the former belongs with the mineral state even if the latter does not. Topics covered include a brief summary of how Colorado courts approach the categorization of minerals, an outline of the real-world contextual factors and background principles of construction for contract drafting and a description of the features of frac sand.

In this paper, a series of cyclic torsional shear tests (TST) were used to study the cyclic undrained behavior and liquefaction resistance of saturated transparent sand manufactured by fused quartz. It was found that the saturated transparent sand has the similar cyclic undrained behavior with saturated natural sands. The mobilized angle of shearing resistance of saturated transparent sand is around 42.6° within the range of saturated natural sands which have angular shape. The saturated transparent sand has a similar trend of shear stress ratio versus number of cycles, but the liquefaction resistance is a little of higher than saturated natural sands. [ABSTRACT FROM AUTHOR]

Concrete is the most extensively used construction material in the world, second to water. Increasing rate of urbanization and industrialization has lead to over exploitation of natural resources such as river sand and gravels, which is giving rise to sustainability issues. It has now become imperative to look for alternatives of constituent materials of concrete. Waste foundry sand, a by-product of ferrous and non ferrous metal casting industries is one such promising material which can be used as an alternative to natural sand in concrete. In last few decades, several studies have been conducted to investigate the effect of addition of waste foundry sand as partial and complete replacement of regular sand in concrete. It has been found suitable to be used as partial replacement of sand in structural grade concrete. A number of properties have been reviewed in the current paper, the results observed from the various studies depict that replacement of foundry sand to a certain extent enhance the durability as well as strength properties of the concrete but simultaneously decreases the slump value with the increase of replacement level of waste foundry sand. [ABSTRACT FROM AUTHOR]

Proppants are widely used in hydraulic fracturing operations. They consist of solid particles with specific strengths and are used to keep the fractures open to enhance well production. They can be natural sand or artificial ceramic materials. Most ceramic proppants are alumina-based, using kaolin and bauxitic clays as the raw materials. The acid resistance of the fracturing proppant is an essential property. Acids are sometimes needed to clean the fracture by removing scale and clays that reduce the fracture conductivity. In this study, several experiments were conducted using a see-through cell, and an aging cell with 10 wt% HCl, mud acids (6.0 wt% HCl, 1.0 wt% HF and 12.0 wt% HCl, 3.0 wt% HF), i.e., (6:1 and 12:3), and formic (HCOOH), trisodium salt of N-(hydroxyethyl)-ethylenediaminetriacetic acid (Na 3 -HEDTA) and HF mixtures up to 350 °F. The effects of varying acid system, temperature, soaking time, static and dynamic conditions were examined. The supernatant of solubility tests was analyzed with Fluorine Nuclear Magnetic Resonance ( 19 F NMR) to identify the reaction products. Key elements concentrations were measured using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). A Zeiss Axiophot microscope was used to acquire images for the proppant particles to study particle shape and effect of acid solubility. Proppants were then analyzed by X-ray fluorescence (XRF) and X-ray diffraction (XRD). The proppant was sieved before and after the experiments. The residual solids were dried and analyzed using a scanning electron microscope (SEM) with Energy Dispersive X-ray Spectroscopy (EDS) capabilities. Effects of acid dissolution on mechanical performance of the proppants were also tested using an automated load frame. The results show that bauxite has a minimal solubility of 0.5 wt% in 10.0 wt% HCl. The proppant is readily soluble in different mud acids, 56.0 wt% dissolved in some cases. The amount dissolved increases with temperature, soaking time, acid concentration, and dynamic conditions. The fines generated and the changes in grain size distribution are detrimental to the proppant conductivity. 19 F NMR showed aluminum fluoride complexes with different mud acids due to the high Al/F affinity. XRF showed that the solubility of the proppant occurs mainly in mullite and maghemite due to their high reactivity. Crush resistance test shows a direct relationship between solubility and mechanical strength of bauxite. Assessing solubility effects will help to better design acid treatments without jeopardizing the integrity of the proppant. [ABSTRACT FROM AUTHOR]

Dynamic impact loading may cause gradual crushing of soil grains, especially when soil grains are characterised by weak strength or when the geologic history of the soil has influenced on material fatigue. The aim of the work is to identify the soil crushability during dynamic compaction, as well as the effect of a gradual grain crumbling on changes of the maximum dry density and the uniformity coefficient. All tests were performed for genetically different non-cohesive soils from various Polish areas. In Pleistocene river sands and in the sea sands – repeated compaction does not improve the coefficient of uniformity and does not result in significant changes in the maximum dry density. In the river sands from Holocene alluvial deposits, multiple compaction causes a significant increase in value of ρ d max . In glaciofluvial sands and gravel multiple compaction increases the maximum dry density and uniformity coefficient of compacted soil. The monomineralic soils was characterised by values of C U < 3.0, and the polymineralic soils – by values of C U ≥ 3.0. [ABSTRACT FROM AUTHOR]

Despite the devastating short- and long-term consequences of resource-related environmental crimes, rampant illegal soil and sand mining continues worldwide. In countries such as India and Italy, organized crime groups have emerged as prominent illegal suppliers of soil and sand. The proposed study focuses on an understudied research area at the intersection between organized crime and environmental crimes, and offers a trans-comparative study of illegal soil and sand mining conducted by Indian and Italian organized crime groups with two main objectives. First, a comparative analysis of the organizational mechanisms, operational practices, threat management, and supporting cultural, regulatory, and policing factors is conducted. Second, a discussion of how these groups reflect mainstream models and theories of organized crime is offered. [ABSTRACT FROM AUTHOR]