Academic literature on the topic 'The use of mine waste as a construction material'

The need for modernization and adjustment of existing road infrastructure to European Union requirements will result in the need for processing thousands tones of waste. The amount of waste received from road repairs and road demolitions, as well as technological by-products in Poland may be estimated at the level over 2.5 million tones, which is almost 2% of all waste production. Construction waste recycling is truly justified in this case, together with waste management according to the provisions of national and international law. One of such products is dust generated as a side effect of stone processing in a Casey mine in Ireland. Laboratory tests of the new material compositions with the use of waste from this mine not only realize the general aims of economic and ecological assumptions, but also allow increasing quality of a new product which is an asphalt-concrete composite. In order to check the properties of the use of a filler in a form of Hornfels Ireland powder there was conducted a series of special tests on the asphalt concrete testing the wearing course. Hornfels Ireland powder produced as a waste material of an aggregate processing in Cassey Quarry is a useful material, which may be successfully used as a component in a process of WMA production.

We examined the national mine waste registries from seven European countries, created to fulfil the requirements of the “Mine Waste Directive” (2006/21/EC), for their potential use as an initial source of information for the valorisation of specific mine waste deposits for their resource recovery. A set of parameters for mine waste valorisation was defined and divided into three groups: the “basic”, the “metal-centric” and the “material-centric” group. The “basic” group of 19 parameters considers properties of the mine waste deposit, including the location, history, homogeneity and quantity, among others, while the other two groups relate to the two desired material recovery types. The “metal-centric” group of parameters contains the six parameters needed to preliminarily assess the potential to valorise mine waste for metal extraction, while the “material-centric” group contains the nine parameters needed to consider the use of mine waste for the production of different construction materials. National mine waste registries from Slovenia, France, Spain, Italy, UK, Hungary and Portugal were reviewed to determine whether they contain information about each of the parameters. In line with the objectives of the Mine Waste Directive, the national mine waste registries were developed to reduce or prevent environmental damage, and not to enable resource recovery from mine waste. The registries contain most of the information for the parameters in the “basic” group, less information for the parameters in the “metal-centric” group and almost no information to define the parameters in the “material-centric” group. The conclusion is that national mine waste registries could serve only as an initial source of information, and more detailed information must be obtained from other sources. This misses an opportunity to see these sites as a resource, and not only as a potential source of pollution, given the urgent need to find alternative stocks of metals within the EU (European Union).

The road construction sector is a worldwide high consumer of natural aggregates. The use of unusual industrial by-products in road techniques can contribute to the conservation of non-renewable natural resources and the reduction of wastes produced by some industries. Phosphate waste rocks could be considered as potential alternative secondary raw materials in road construction. The use and valorization of these wastes is currently limited according to the Moroccan guide for road earthworks (GMTR). The guide has classified these materials as waste products, which consequently, cannot be used in road construction. However, phosphate waste rocks are sedimentary natural rocks which have not been subjected to any transformation other than mechanical fragmentation. The goal of this paper is to discuss key-properties of various phosphate mine waste rocks (PMWR) to be used as road materials. Samples were taken from different stockpiles in the phosphate mine site of Gantour in Morocco. The different waste rocks samples were characterized in terms of their physical, geotechnical, chemical, mineralogical and environmental properties using international testing norms. The obtained results showed that the studied PMWR presented satisfying characteristics; the specific (particle) density: ρs > 26 kN/m3, Los Angeles abrasion: 45% < LA < 58%), methylene blue value MBV < 1 g/100g, organic matter: OM < 1% and plasticity index: PI < 20%. All PMWR were confirmed as possessing the requested geotechnical properties to be used as materials for embankments. Moreover, leaching tests showed that none of them released any contaminants. In field application, these materials have been also successfully used in in situ experimental pilot testing. Therefore, the PMWR have to be classified in the category of natural aggregates that are similar to conventional materials.

This paper deals with the potential reuse of coal mine waste rocks (CMWR) as an alternative material for road construction to conserve the natural resources and sustainable management of mining waste. The investigation was conducted through the determination of the chemical, mineralogical, geotechnical properties, and acid mine drainage formulation of CMWR as well as economic feasibility. This waste was used either alone for embankments and mixed with stabilizing agents fly ash (FA) and hydraulic road binder (HRB) for pavement applications. The experimental results confirmed that weathered CMWR can be successfully used alone as a sustainable alternative material for the embankment. Furthermore, the use of stabilizing agents in the following ratio CMWR:FA:HRB = 80:20:5 allow the use of CMWR in road sub-base layers for high-traffic pavements. Also, the environmental investigations showed that CMWR does not present any potential contaminating risk on the surrounding environment and most of the pyrite particles were already oxidized. Therefore, the environmental impact of acid mine drainage produced by pyritic waste throughout its life cycle can be neglected. Finally, an economic case study confirmed the workability of CMWR reuse in a radius of 29 km around their dumps by resulting in a lower cost compared with conventional materials.

This research work analyses the influence of the use of by-products from a fluorite mine to replace the fine fraction of natural aggregates, on the properties of Ultra-High-Performance Fibre-Reinforced Concrete (UHPFRC). Replacing natural aggregates for different kinds of wastes is becoming common in concrete manufacturing and there are a number of studies into the use of waste from the construction sector in UHPFRC. However, there is very little work concerning the use of waste from the mining industry. Furthermore, most of the existing studies focus on granite wastes. So, using mining sand waste is an innovative alternative to replace natural aggregates in the manufacture of UHPFRC. The substitutions in this study are of 50%, 70% and 100% by volume of 0–0.5 mm natural silica sand. The results obtained show that the variations in the properties of consistency, compressive strength, modulus of elasticity and tensile strength, among others, are acceptable for substitutions of up to 70%. Therefore, fluorite mining sand waste is proved to be a viable alternative in the manufacturing of UHPFRC.

The use of geopolymer in pavement constructions is strongly encouraged. Many studies have demonstrated the vast potential of using industrial-by-products-based geopolymers. This paper discusses the modification of asphalt binders with geopolymers, namely geopolymer-modified asphalt (GMA) and geopolymer-modified asphalt mixture (GMAM). In addition, curing geopolymer materials, engineering properties, production techniques, and prospective utilisation in the pavement construction, such as durability and sustainability, are also discussed. The literature review showed that many industrial by-products, including red mud, blast furnace slag, fly ash, and mine waste, are used to produce geopolymers because of the metal components such as silicon and aluminium in these materials. The geopolymers from these materials influence the rheological and physical properties of asphalt binders. Geopolymers can enhance asphalt mixture performance, such as stability, fatigue, rutting, and low-temperature cracking. The use of geopolymers in asphalt pavement has beneficial impacts on sustainability and economic and environmental benefits.

Abstract In some regions of the German New Federal Lands, residues from early mining characterise the radiological situation and can also influence the radon concentration in buildings. Construction on waste rock with increased radium concentration, the use of waste rock as building material and construction above shallow mine shafts and adits are important in this connection. In Saxony, for instance, one has to reckon with probably hundreds of buildings that may be influenced by radon from shallow mine workings. Very short-term changes of radon concentrations in buildings over several orders of magnitude was well as their close temporal correlation with the underground airflow clearly indicate influences from underground. In Schneeberg and Schlema, fluctuations of radon concentration in buildings of several 10,000 Bq.m-3 within one hour were observed. In Schneeberg, the old mine was ventilated artificially by installing a ventilator with an output volume of 500 m3min-1. Thus the radon concentration in buildings of the central city area has been reduced. In Schlema, the radon rich shafts of early mining are ventilated at present by the still active ventilation system of the suspended uranium ore mining. In 1992, during the first six months, 4.5 x 109 m3 of mine air with a radon activity of 6.3 x 1014Bq were extracted from the mine. If the mine ventilators are switched off, radon concentration in buildings over mine shaft increases sharply by two orders of magnitude.

This paper investigates an alternative use of sterile aggregate materials which may arise from various construction applications in conjunction with other low-cost mineral raw materials to remediate the acid mine drainage phenomenon. This study is based on the combination of unprocessed mineral raw materials, as well as on the basic concept of the cyclic economy where the conversion of a waste into a raw material for another application can be achieved. In this study, in order to examine the remediation, in lab scale, of the drainage waste water of Agios Philippos mine, an experimental electrically continuous flow-driven forced device was constructed, enriching the research gap relative to this type of remediation approach. Through this experimental device, the use of certain mixes of mineral raw materials (serpentinite, andesite, magnesite, peat, and biochar) was studied. Our results focus on the impact of the studied mineral raw materials and especially on their synergy on the water purification potential under continuous water flow operation. Using the new 7-day experimental electrically continuous flow-driven forced device with certain mixes of mineral raw materials, the increase of pH values from 3.00 to 6.82 was achieved. Moreover, with use of the experimental device, the removal of toxic load was achieved, and more specifically the concentration of Fe was decreased from 6149 to 1300 ppb, Cu from 8847 to 35 ppb, and Zn from 285,458 to 50,000 ppb.

AbstractIn recent years, the economic importance of gangue mined during coal production has changed and it is currently treated more and more often not as waste but as a source of mineral resources for economic use. The overriding objective throughout the reclamation process of open-pit mines associated with the utilization of external material is to make sure that the placement of waste rock on the surface does not cause damage to the environment. The paper presents results of the diagnosis and evaluation of the possibility of filling open-pit mine workings with mining waste or other materials, for example aggregates produced on the basis of gangue, originating in the Janina Mine mining plant (a subsidiary of TAURON Wydobycie S.A.). The study involved aggregate or coal silts from dewatering on the filter presses. The evaluation refers to the legal aspects and takes the requirements of pollution prevention into account, with a particular emphasis on soil, surface water and groundwater. The analysis of the potential impact on the soil and water environment of the project involving reclamation of the open-pit excavation with the use of minerals or waste from coal mining was carried out based on a study of the total content of sulfur and other elements in the samples pierwiastków (As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, V and Zn), as well as of the leaching of components. Moreover, an examination of the coefficient of permeability and porosity was conducted, which allowed the suitability of the material for the construction of insulating layers to be determined. The physical and chemical analyses were conducted on a total of over a dozen samples of waste rock, a byproduct of the enrichment of coal in the Janina Mine plant. The specific studies of the total sulfur content were conducted for the 16 primary samples scattered into 15 fractions each. Moreover, the so-called secondary samples were created, meaning that fine fractions of less than 20 mm and less than 10 mm were rejected. The total content of the selected components was examined for such crafted samples and their concentrations were determined in the leachable form (batch test 1:10). In the case of use of waste rock as an aggregate for quarry reclamation, a comparative analysis was applied to the legal requirements assigned to the mining waste and the quality of soil and water environment. Based on the conducted studies, it has been concluded that the coal silts (filter cakes) are characterized by good insulating properties and can be used for waterproofing objects, especially in the industrial, communications and mining areas. However, coal silts do not meet the quality requirements, mainly due to their slightly increased chlorides content, in addition to being a waste, which in some cases limits the possibility of their use. The best quality parameters were found for the gangue from the Janina Mine (on the basis of which aggregates are manufactured), but deprived of fine fractions. Physical and chemical analyses of the total content of elements in the secondary samples showed that the obtained values are within the allowable ranges determined by appropriate regulations for the vast majority of samples. The limit of 1% was assumed for the sulfur content. The conducted research on the leaching of pollutants indicates that the tested samples do not introduce contaminants exceeding the limit values for the analyzed metals and sulfates. Only single exceedances of the analyzed parameters are observed. The test results allow to conclude that it is possible to obtain a useful product that meets the requirements of environmental protection, but only after the rejection of fine fractions of the waste material.

Storage of mine tailings and waste concrete imposes economical and environmental impacts. Researchers have attempted to reuse wastes as construction material by utilizing ordinary Portland cement (OPC) to stabilize them. This method, however, has a number of limitations related to OPC. In this research, a recent technology called geopolymerization is used to stabilize mine tailings and concrete waste so that they can be completely recycled and reused. The research includes three main parts. The first part studies the effect of different factors on the mechanical properties, micro/nano structure, and elemental and phase composition of mine tailings-based geopolymer binder. The second part investigates the feasibility of producing geopolymer bricks using mine tailings. The physical and mechanical properties, micro/nano structure, durability, and environmental performance of the produced bricks are studied in a systematic way. Moreover, the enhancement of the mine tailings-based geopolymer bricks by adding cement kiln dust (CKD) is studied. The third part of the research investigates the recycling of the fines fraction of crushed waste concrete to produce binder through geopolymerization in order to completely recycle concrete waste. The results indicate the viability of geopolymerization of mine tailings by optimizing the synthesis conditions. By properly selecting these factors, mine tailings-based geopolymer bricks can be produced to meet the ASTM standard requirements and to be environmentally safe by effectively immobilizing the heavy metals in the mine tailings. The physical and mechanical properties and durability of the mine tailings-based geopolymer bricks can be further enhanced by adding a small amount of CKD. The results also show that the fines fraction of crushed waste concrete can be used together with fly ash to produce high performance geopolymer binder. Incorporation of calcium in the geopolymer structure and coexistence of the calcium products such as CSH gel and the geopolymer gel explains the enhancement of the mine tailings-based geopolymer bricks with CKD and the high performance of geopolymer binder from the waste concrete fines and fly ash. The research contributes to sustainable development by promoting complete recycling and utilization of mine tailings and concrete waste as construction material.

Thesis (M.S.C.E.)--University of Toledo, 2008.
Typescript. "Submitted as partial fulfillment of the requirements for Masters of Science degree in Civil Engineering." "A thesis entitled"--at head of title. Bibliography: leaves 90-92.

Every 1 t of china clay produced in the UK generates 9 t of waste material. A limited quantity of the coarser waste has beneficial use as a building stone or secondary aggregate in concrete and asphalt, but there are currently limited uses for the finest waste fraction. ‘Mica’ waste is a mixture of fine minerals and is one of the forms of waste with little beneficial use other than the restoration of old quarries. Looking for innovative solutions for the needs of a new Eco-town in the UK and with an aim to find new commercially viable and low environmental impact uses in construction, this PhD introduces the idea of using the china clay waste in alkali-activated binders. First, it was investigated whether the contained mica mineral could be used as an alkali-activated binder. This was done using different MAS NMR and XRD analysis, and mechanical strength tests based on European standards. The material was shown to have low reactivity and some direct trials of alkali-activation of thermally treated mica mineral produced in average weak binders. Later, three series of alkali-activated binders were studied, one based on Ground Granulated Blastfurnace Slag (GGBS), one based on Fly Ash (FA) and one based on a 50%GGBS-50%FA blend (50/50). The china clay waste was incorporated in selected optimum binders from the three series as aggregate to make mortars and concrete. Compared to control specimens, the test specimens using the china clay waste always showed lower strength. It is suggested that the high water demand of the waste is the main problem. When the waste was used in mortars, the impact of the water declined over time, with sand waste from china clay extraction showing approximately equivalent strength to the control silica based mortar after 6 months of curing for the GGBS and 50/50 series. For the same series, mica-waste specimens gave about 50% of the strength of the control mortar on the 7th day of curing but increased to 70-80% of the control compressive strength at 6 months. In the FA series, the impact of additional water resulted in very low strengths and that series did not proceed in concrete making. The concrete design was accompanied by an environmental analysis to ensure environmentally beneficial outcomes were obtained. Testing in compression shows a similar decreasing strength for the Portland and the alkali-activated series for increasing amounts of waste used. However, the test specimens of the GGBS series showed potential for replacing Portland control specimens. The potential for making blocks and tiles using the new concrete would be greater if the mix design is optimized. Durability testing will be required on an optimized design and final product, but initial analysis of test results and the literature indicate this is unlikely to be a concern. Not using the final product to run durability tests would lead to arbitrary conclusions. The environmental analysis shows that although the carbon emissions would be reduced using alkali-activated concrete, most of the other environmental impact categories would be affected negatively which has to be considered when making the final decision on whether to use this new material in the Eco-town or elsewhere.

The project cost overruns instigated through the loss of construction materials lowers the profitability of each stakeholder significantly. The purpose of this single case study was to explore strategies managerial leaders of a large construction firm used to counteract material cost overruns successfully. The diffusion of innovation theory was the conceptual framework for this study. The target population consisted of 6 managerial leaders with experience in large construction projects adhering to waste management standards and industry certifications. Data were collected using semistructured interviews and review of company documentation. The data analysis approach involved the content analysis research method to interpret and code the verbatim transcriptions of interviews into categories. The 2 principal categories from the study data were material management and planning and the supply chain and logistics. The results of the study yielded evidence of 2 strategies to counteract the material cost overruns, which were to strengthen partnerships with the suppliers and to hold regular audits at the project sites. The implication of this study for social change includes the potential to conserve depleted land minerals and valuable land reserves from becoming landfill by providing construction managers with information about strategies to counteract material cost overruns.

A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy in Science to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, 1985
This volume contains a record of research carried out over the past two decades into problems associated with civil engineering and mining construction materials. Although the various parts of the work were initiated as a result of problems that arose in the Witwatersrand region, the results of the research have in many cases evoked intense interest from other parts of the world. For example, the work on soluble salts in road bases has been taken up in Saudi Arabia and other desert regions, while that on the stability of waste rock dumps has been adopted as a basis for rock dump design in the United States of America. The research revolves entirely about materials, usually, waste, either produced by the mines and reused or disposed of by civil engineers; or reused to provide support by the mines · themselves. The main aim and end result of the research has been a more effective and efficient use of materials and better protection and control of the local environment.
Andrew Chakane 2021

The WMC Fertilizers operation at Phosphate Hill, north-west Queensland, began production of ammonium phosphate fertilizer in late 1999. In the production process, Cambrian marine phosphorites are crushed and dissolved (acidulated) in sulphuric and phosphoric acid to produce stronger phosphoric acid and, as a by-product, phosphogypsum (PG). The phosphoric acid is used, with ammonia, for fertilizer production while the PG is permanently stored on-site in gypsum stacking facilities. In common with other fertilizer plants, the volume of PG in storage at Phosphate Hill has increased rapidly. Eventually tens of millions of tonnes of the material will need to be maintained in permanent facilities. Above-ground stacks, such as those currently used, will be subject to erosion, potentially forming sources of pollutants for the surrounding pastoral country. An alternative option is to store the PG in the voids left after mining of the phosphorite ore body. This would immediately negate most opportunities for erosion of, and contamination from, the storage facilities. This study was instigated to assess the likely impact of in-pit disposal. Very little work had been done on characterizing the PG produced at Phosphate Hill. A single initial set of analyses taken from samples obtained during the commissioning period identified the major components and subjected the material to rigorous mechanical testing. By contrast, this study has focussed on fully identifying the mineralogy, chemistry, radiochemistry and physical characteristics of the PG in its two main species: the hemihydrate (bassanite - CaSO4.0.5H2O) as it is produced from the phosphoric acid plant and the dihydrate (gypsum - CaSO4.2H2O) that is transported from the re-slurry tank into the gypsum stack for storage. In addition, the liquid component of the PG slurry, derived from acid process water that is recirculated through the stacking system, has also been analysed. The results show that the four species of calcium sulphate can be found in the PG. Bassanite (CaSO4.0.5H2O) is dominant in the hemihydrate filter cake but also remains in the stack material. Dihydrate gypsum (CaSO4.2H2O), including species with extra H2O molecules (identified as *.0.5H2O), dominates the stack gypsum but also occurs at low levels in the hemihydrate filter cake. Anhydrite (CaSO4) is also found at low levels within samples from both areas. Quartz (SiO 2) is the other dominant mineral in the PG assemblage. This is at significant levels (>20%) and causes the PG to be notably different to that produced elsewhere in the world, where quartz makes up <1% of the total. The high volumes of this mineral result from the make-up of the parent phosphorite ore body, which has a comparatively high level of chert and silicified siltstone and shale. P2O5 levels are elevated and relate primarily to the presence of co-precipitated and reprecipitated phosphates and remnant phosphoric acid with very minor amounts of unreacted phosphorite and phosphatised chert and siltstone. Mica (paragonite [NaAl2(Si3Al)O10(OH)2] and probably muscovite [K2Al4[Si6Al2O20](OH,F)4] and glauconite [(K,Ca,Na)~1.6(Fe3+,Al,Mg,Fe2+)4.0Si7.3Al0.7O20(OH)4] sourced from the ore body) was a consistent presence at low levels in the PG mix. An unidentified amphibole was also found, although some doubts exist as to the accuracy of the XRD technique to adequately identify such minerals at the low levels seen here. If correct, the latter is probably from the hornblende group (magnesiohastingsite to hastingsite) that occurs in the basement Kalkadoon Granodiorite, or from the basement Proterozoic metasediments of the Plum Mountain Gneiss and Corella Formation. Various clays, most commonly smectite ((½Ca,Na)0.7(Al,Mg,Fe)4[(Si,Al)8O20](OH)4.nH2O) and clinoptilolite ((Na,K)6[Al6Si30O72].24H2O) were also consistently present. Major element analyses are consistent with the mineralogical interpretation. Elements, apart from Ca, S and Si and including F, were at levels similar to those found in PG manufactured at other sites around the globe. Trace elements showed elevated levels of Ba, Mn and Pb relative to foreign-sourced PG. This appears to reflect the primary and secondary (weathering products) mineralogy of the ore body. Crystal morphology was also shown to be similar to that produced abroad, at sites as diverse as the USA, north Africa and the Middle East. The gypsum component of the Phosphate Hill PG appears to contains fewer acicular crystals and no swallow-tail twins were observed, unlike at other sites. Massive clusters are common. Radiochemical analyses have identified U-238, Po-210, Pb-210, Ra-226 and Rn-222 as being present in the ore and throughout the manufacturing process. All are present to varying degrees in the PG but the U-238 tends to partition more into the fertilizer. None of the radionuclides occur at levels that could be considered a risk. However, the study has identified that recirculation of the fluids through the re-slurry-stacking circuit is concentrating the radionuclides occurring in the process water. This issue will need to be monitored and addressed by the Company in future. The second part of the project has been to study the effects of dissolution on the PG if placed into surface mining voids as backfill. At Phosphate Hill, potential dissolution of mine backfill material can be derived from two sources. The first is the monsoonal "wet season" over summer, where individual rain events can result in over 150mm of rain falling in the space of a few hours, leading to flash flooding and inundation of wide areas around the local watercourses. This has the potential to result in the temporary submergence of any of the backfilled areas located within the flood plain. The second source is from interaction of the PG with the groundwater. The latter will occur because the Beetle Creek Formation, which hosts the ore body, also contains the local aquifer and post-mining recharge will see the SWL return to pre-mining levels, well above the floors of the pits. Dissolution experiments were performed using hemihydrate and two forms of dihydrate PG, simulating approximately two years’ annual rainfall/intermittent full inundation of a PG backfill pile by either groundwater or floodwater. The dihydrate PG was newly deposited material that still contained high levels of fluid and "aged" dihydrate that had been on the stack for 4-6 months and was dry. Analyses of the dissolution and the pre and post-dissolution PG showed that highly contaminated dissolution would occur in the first 2-3 flushing events and that levels of contaminants fall rapidly with further flushing. The major long-term contaminant has been identified as sulphates and acid derived from gypsum dissolution. Ca and total P are also significant. Radionuclide analysis of leachate could not be undertaken in this study but should be considered for any future studies, if the Company plans to utilise in-pit disposal of PG. Gypsum dissolution is also likely to be a long-term problem in that the aquifer is essentially a closed system. This, along with the dominant flow direction, will result in concentration of any contaminants in the southern part of the aquifer. Basic simple modelling of the effects of a sulphate-rich solution mixing with the groundwater at its current quality suggests that the sulphate may reach levels of concern for human consumption (i.e. >500mg/l) with an input of contaminated fluid the equivalent of <25% of the total volume of the aquifer. As the site is covered by active pastoral leases the effect of sulphate contamination of groundwater on cattle was also considered. In this environment problems occur at sulphate levels of ~1000mg/l which the modelling suggests would not occur until a mix of 50% leachate to 50% groundwater was achieved. Although this appears to be a remote possibility for contamination of the whole aquifer, the very high transmissivity of the aquifer will result in a polluted plume being drawn directly into wells that are pumping, which could easily result in the ingestion of poor quality water by cattle drinking from troughs supplied by any such bore. Acidification of the groundwater could also possibly occur with the escape of acid leachate into the aquifer, with the pH of the water rapidly falling below the preferred minimum of pH 6 at relatively low levels of mixing (10% leachate to 90% groundwater). Acidification to this extent can cause acidosis in cattle, a condition that is potentially fatal. Phosphorous is also present in high levels in the PG leachate. There is potential for this to lead to outbreaks of toxic cyanobacteria in water storage tanks and troughs in the warmer months, which can result in fatalities in cattle through liver or respiratory failure. However, this potential may be buffered by the likely acidity of any high-P leachate, as cyanobacteria prefers neutral to alkaline water conditions. Although contaminated leachate can be largely contained by use of liners and capping material, the use of PG as backfill at Phosphate Hill faces challenges that would be extremely difficult to overcome. The mining method leaves walls that are sub-vertical (>70º) and exposes the full ore seam on the down-dip side of the ore body. Pit floors have a dome-and-basin morphology. Although the latter could be flattened and lined, the steep walls, with their exposures of abrasive, sharp-edged phosphorite would preclude the use of most lining materials. The scale of earth- moving and lining required would also be cost-prohibitive. The type of PG used for backfilling operations and the method of delivery also create difficulties. Filter cake hemihydrate PG would require a very large truck fleet and/or the construction of a new overland conveyor. Once deposited, the material’s tendency to form large, loose clumps would allow rapid through- flow of fluids. PG slurry could be piped directly to its deposition point, requiring the construction of an extensive pipe network, but is otherwise completely unsuitable for the task due to the liquid component. Dry dihydrate PG is the best material for backfill. However, it would also require a very large truck fleet and the act of rehandling the material from stack to pit would create dust problems for the term of the rehandling exercise. After deposition the leachate problem would still exist, albeit produced at a slower rate due to the dihydrate’s lower permeability. The leachate problem could be countered by using a layer-cake style of construction where calcareous rocks are interlayered with PG to neutralise any fluids derived from the PG. Despite this, other engineering and environmental issues probably preclude the use of even this method of backfill. This study has produced the base-line information required for any future work involving the PG, such as the recommendation for trials of in-pit dumping to go ahead, observing a range of conditions. As a result, it is recommended that WMCF only use dihydrate PG as backfill in areas that are well above the natural standing water level and that have been adequately lined. The majority of PG will still need to be stored in lined and capped stacks, as are currently used. It is also recommended that the radionuclide content of the recycled stack fluids being regularly monitored and plans drawn up to deal with the contaminated fluids if it proves necessary. Future research should also be conducted on radionuclide transport and behaviour in PG leachate.

Guidelines for Mine Waste Dump and Stockpile Design is a comprehensive, practical guide to the investigation, design, operation and monitoring of mine waste dumps, dragline spoils and major stockpiles associated with large open pit mines. These facilities are some of the largest man-made structures on Earth, and while most have performed very well, there are cases where instabilities have occurred with severe consequences, including loss of life and extensive environmental and economic damage. Developed and written by industry experts with extensive knowledge and experience, this book is an initiative of the Large Open Pit (LOP) Project. It comprises 16 chapters that follow the life cycle of a mine waste dump, dragline spoil or stockpile from site selection to closure and reclamation. It describes the investigation and design process, introduces a comprehensive stability rating and hazard classification system, provides guidance on acceptability criteria, and sets out the key elements of stability and runout analysis. Chapters on site and material characterisation, surface water and groundwater characterisation and management, risk assessment, operations and monitoring, management of ARD, emerging technologies and closure are included. A chapter is also dedicated to the analysis and design of dragline spoils. Guidelines for Mine Waste Dump and Stockpile Design summarises the current state of practice and provides insight and guidance to mine operators, geotechnical engineers, mining engineers, hydrogeologists, geologists and other individuals that are responsible at the mine site level for ensuring the stability and performance of these structures. Readership includes mining engineers, geotechnical engineers, civil engineers, engineering geologists, hydrogeologists, environmental scientists, and other professionals involved in the site selection, investigation, design, permitting, construction, operation, monitoring, closure and reclamation of mine waste dumps and stockpiles.

<p><b>Bentonites</b> are rocks mostly consisting of swelling clay minerals. They were first described from the Cretaceous Benton Shale near Rock River, Wyoming, USA. </p> <p> Because of their useful properties (e.g. highly adsorbent, cation exchanging, swelling), bentonites have many uses, in industry (among them as drilling mud, purification agent, binder, adsorbent, paper production), culture (for e.g. pottery) and medicine/cosmetics/cat litter, civil engineering, and in the future even in the disposal of high-level nuclear waste. </p> <p> Particular chemical characteristics of bentonite clay minerals are rather variable but critically determine their suitability for a particular application. </p> <p> The 15 specialist authors discuss bentonite terminology, classification and genesis and use in eight chapters. Individual chapters deal with the methods bentonites are analysed with, their properties and performance in terms of parameters such as cation exchange capactiy, rheology, coagulation concentraion, water uptake capacity, free swelling, and electrical resistivity (amongst others). </p> <p> A chapter is dedicated to the sources of bentonites, the technology employed to produce them, and how quality control is carried out both in the mine and the laboratory. A further chapter is dedicated to methods of processing the mined material, different activation methods, drying, grinding, and purification. </p> <P> Use cases for bentonites are discussed in a chapter of its own. References, a section on norms and standards, and a list of abbreviations complete the text. </p> <p> The volume addresses students, researchers, and professionals in the mineral industry dealing with bentonite and their clay-mineral constituents, quality assessement and control, and persons that use bentonites in their products. </p>

AbstractThe future sustainable built environment focuses mainly on environmental conservation and technological innovation and development. However, with infrastructure development, the consumption of raw materials such as cement, gypsum, sand, and stones increases. Therefore, use of industrial waste as raw material in construction shall be proposed as a sustainable and environment friendly alternative. Also, the higher demand for mineral commodities have led to increased mining and hence increased mining waste. The mine tailings being the wastes from rocks and minerals processing, are generally rich in Si, Ca, Al, Mg, and Fe, and also have considerable amounts of heavy metals and metalloids such as Pb, As, Co, Cu, Zn, V, and Cr. When tailings contain sulphide minerals, it may also lead to acid mine drainage. This makes the effective and efficient recycling and reuse of mine waste a major environmental concern. However, the physical, mineralogical and chemical composition of the mine tailings renders it a suitable material for use in civil engineering applications. This paper discusses the use of mine tailings of different origins for different civil engineering applications such as bricks, ceramics, fine aggregates, coarse aggregate and cementitious binders. This approach has a potential to reduce the demand on existing natural resources to face the demands of the exponentially developing infrastructure.

AbstractThis paper aims to present a methodology for reusing and recycling scrap timber from building sites using augmented reality and flexible digital models. The project we present describes a process that enables existing material to be reused and repurposed such that the designed model is updated by the digital inventory of digitised offcuts/waste elements.

A conspectus based upon a compelling topic, namely, versatility of cockle shell use in concrete to replace partially the natural coarse aggregates and river sand, which is yet to be investigated, is covered in this chapter. An introduction to enlighten the reader with this promising waste material precedes a review of environmental issues with cockle shell which would reduce harm to environment and preserve natural materials for future generation. Cockle trade is an important subtitle that covers cockle shell waste generation, research, and development related to the deployment on the use of cockle shell, processing cockle shell for making construction material are discussed in detail. Experiments were conducted, and the test data revealed that the use of cockle shell as partial replacement of coarse aggregates enhanced the strength of concrete and as partial replacement of sand improved the performance of mortar bricks.

This chapter deals with the characterization and assessment of iron ore tailings (IOT) as raw materials for the construction industry. This chapter specifies the production process of iron ore and generation of waste material followed by listing the nature and prospective issues of IOT. Methods of IOT characterization are explained through five elements, which are chemical composition, leaching behavior, thermal stability, mineralogical characterization, and morphology. The experimental program and research results of this study are explained in six subtitles, namely chemical composition, leaching behaviour, thermal stability, x-ray diffraction pattern, Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FESEM/EDX). Results revealed that the IOT materials are suitable for use in construction and building industries due to their substantial silica and alumina contents and could possibly be used to fabricate paving blocks, sand-crete blocks, mud blocks, geopolymer bricks, and ceramic floor tiles.

Sustainable (environmentally friendly) modern construction is not limited only to use of natural and environmentally friendly materials. The concept of the construction is an important factor and that is applied to local materials, especially if they come from renewable sources. The sustainable (environmentally friendly) building principles, methods of construction from straw, the essential building requirements for construction from straw are discussed in the article. Straw as a building material used for a very long time, but this usage is often associated with certain mistrust, fears: the building will burn, the mice, rats are attacking, etc. Straw building uses raw materials which are agricultural waste. Buildings constructed from straw decompose in the end of their lifecycle and the construction waste in the area of construction is biodegradable, consequently, it is not necessary to take them away to a landfill. The evaluation of the global and Lithuanian experience of using straw and the structures in which straw are used shows, that the essential requirements can be provided if the straw and timber-framed buildings with straw as a heat insulating material are constructed properly, they use to meet the essential requirements according to the Law on Construction and the European Council and Parliament Regulation No 305/2011.

Abstract Problems arising from uranium dispersion from mines and mine tailings, and the remediation of uranium contaminated areas, are discussed in this paper. In an experimental remediation study, a mixture of 70 vol.% of uraniferous mining wastes and 30 vol.% of a natural ceramic were used. The preliminary observations are discussed, and a model is proposed for the long term stabilization of mining tailings. Observations and monitoring of contaminated sites carried out during the last 25 years have revealed local impacts of uranium on the environment in Lower Silesia, Poland. Uranium pollution is limited to waste dumps, mine tailings, and their close vicinities at Kowary Podgórze, Radoniów, Kopaniec and Kletno. Uranium dispersion takes place mechanically due to transport by river waters, chemically by rain and ground waters, and anthropogenically when the wastes are utilized in construction. Floods are an additional mechanism responsible for the mechanical dispersion of uranium. As a result of these uranium transport mechanisms, in order to minimize the impacts of uranium on the environment, the covering of dumps with non-radioactive material is suitable only for sites located away from populated areas. Redox reactions have been observed at the Kowary tailings. During these reactions, iron hydroxide (goethite), hematite, and gypsum, are precipitated as solids. These observations provide a good prognosis for the long-term stabilization of radionuclides which can be incorporated into proposals for the construction of tailings sites. Using Eh-pH diagrams (system U-C-O-H, 25°C, 1 bar), UO2 is stable over the whole range of naturally occurring pHs, and is affected by Eh only in the range −0.4 to +0.1 volts in acidic environments, and below −0.4v in basal environments. BaSO4 and RaSO4 are stable under almost the same conditions as UO2. An environmentally significant redox boundary (FeS2 versus Fe2O3) occurs in the middle of the UO2 stability field. The geochemical and environmental behaviour of the elements discussed above suggest a mechanism for stabilizing radionuclides within stored wastes. The solidification of wastes should occur concurrently with naturally occurring redox reactions. During oxidation, an active iron-hydroxide gel is produced. This gel is then dehydrated and converted into limonite (a mixed compound), a monohydrate (goethite), hydro-hematite (Fe2O3·1/2H2O) and hematite (Fe2O3). This reaction occurs in neutral or weakly acidic environments. A key problem in the proposed remediation project, therefore, is pH stabilization in order to maintain the required environment for oxidation and cementation reactions. In order to achieve such an environment and to stabilize the reactions, a construction method is proposed for new waste storage systems, based on mixed layers of waste and barrier components composed of natural materials. The presence of CaO or Ca(OH)2 and anhydrite in the proposed internal membrane will reduce the vertical migration of sulphates. Redox reactions will be responsible for the secondary precipitation (reduction) of uranyl. These same reactions occur naturally during the precipitation of uranium ores. Iron oxidation is the other process in the redox pair required to reduce [UO2]+2 to UO2. The resultant pitchblende is insoluble in normal oxidizing environments. To minimize the dissolution of UO2 by sulphuric acid generated during the iron oxidation reaction, the construction of pH active membranes containing calcium oxide or hydroxide are recommended. These compounds will react with the free acid to precipitate gypsum. Although several elements can be mobilized as a result of oxidation, radium remains in insoluble solid phases such as the common Ca, Ba and Sr sulphates.

Clearance is a very important part of any effective waste management strategy for both operating and decommissioning nuclear facilities. Radioactive waste disposal capacity is becoming an increasingly valuable resource and costs for disposal of radioactive wastes continue to dramatically rise. Considerable cost savings may be realised by efficient segregation of essentially non-radioactive material from radioactive wastes. The release of these materials from licensed nuclear sites for disposal, reuse or recycle without further regulatory controls is commonly referred to by the nuclear industry as “clearance”. Although much effort has been directed at establishing national clearance levels, below which, materials may be released without further regulatory controls, there is little practical guidance regarding implementation into local waste management programmes. Compliance with regulatory clearance limits is a relatively straightforward technical exercise involving appropriate management control and monitoring of the material. Whilst this is sufficient to avoid prosecution for breach of regulatory requirements, it is not sufficient to avoid a myriad of political and public relations land mines. When material is unconditionally released, unless additional attention is given to management of its future destination off-site, it may end up anywhere. The worst nightmare for a waste manager at a nuclear site is headlines in local and national newspapers such as, “RADIOACTIVE WASTE DISPOSED IN LOCAL MUNICIPAL LANDFILL,” or, “RADIOACTIVE WASTE USED AS CONSTRUCTION MATERIAL FOR CHILDRENS PLAYGROUND,” etc. Even if the material were released legally, the cost of recovering from such a situation is potentially very large, and such public relations disasters could threaten to end the clearance programme at the given site, if not nationally. This paper describes how national regulatory clearance levels have been implemented for the decommissioning of the Dounreay nuclear site in the far north of Scotland. It specifically focuses on the management of public relations aspects of clearance in order to limit the exposure to non-regulatory pressures and liabilities associated with clearance programmes from nuclear sites. The issues are put into context for uncontaminated wastes, trace contaminated wastes and management of contaminated land.

Ningyo-toge Uranium Mine is subject to the environmental remediation. The main purposes are to take measures to ensure the radiation protection from the exposure pathways to humans in future, and to prevent the occurrence of mining pollution. The Yotsugi Mill Tailings Pond in the Ningyo-toge Uranium Mine has deposited mining waste and impounded water as a buffer reservoir before it is transferred to the Water Treatment Facility. It is located at the upstream of the water-source river and as the impact on its environment in case of earthquake is estimated significant, the highest priority has been put to it among mine-related facilities in the Mine. So far, basic concept has been examined and a great number of data has been acquired, and using the data, some remediation activities have already done, including capping construction for the upstream part of the Mill Tailings Pond. The capping is to reduce rainwater penetration to lower the burden of water treatment, and to reduce radon exhalation and dose rates. Only natural materials are used to alleviate the future maintenance. Data, including settlement amount and underground temperature is now being acquired and accumulated to verify the effectiveness of the capping, and used for the future remediation of the Downstream with revision of its specifications if necessary.

In the U.S., about 28.5 million tons of municipal solid waste are combusted annually in waste-to-energy facilities that generate 25–30% of ash by weight of the MSW feed. Since some residues were found to contain high levels of lead and cadmium prior to the 1990s, they were commonly associated with environmental pollution. However, for the last years nearly all ash samples have been tested non-hazardous. Research on the beneficial use of combustion residue has been conducted for the past few decades yet the actual ash reuse rate in the U.S. has remained close to 10%. Currently most of the ash is landfilled at considerable cost to the waste-to-energy industry. A consortium of researchers at Columbia University, the State University of New York at Stony Brook, Temple University, and other institutions seeks to develop and to advance the beneficial uses of combustion residues, such as in construction materials or remediation of contaminated abandoned mines and brownfields. This paper describes the search for beneficial use applications and provides an overview of the first year of this consortium.

Low- and intermediate-level radioactive waste was emplaced in the Asse salt mine. Application of backfill materials to provide mechanical stability, plugging of openings and chemical buffering is discussed for closure of the mine. If no remedial action is carried out in the emplacement rooms, degradation of the organic matter cannot be excluded which may result in acidification of the geochemical environment or actinides may be complexed by HCO3− / CO32−. Selection of backfill materials is based on geochemical modeling taking into account the corrosion of the cemented LLW / ILW and degradation of organic waste components. In the present study the evolving geochemical milieu and respective solubilities of Am, Np, Pu, U, Tc, Sr, Cs and I were modeled. The solubilities and the radionuclide inventory define the geochemical source term for each emplacement room. Laboratory experiments were undertaken to verify the modeling predictions. The modeling leads to the conclusion that Portland cement, a Mg(OH)2-based material and crushed salt should be used in different combinations as backfill materials. According to the modeling predictions, the Mg(OH)2-based backfill material provides a long-term stable geochemical environment and scavenges CO2 by formation of (Ca,Mg)-carbonates. The source term calculations were carried out for the presence of the backfill material in the emplacement rooms. The inventory of Pu and U in the waste is sufficient to allow these actinides to reach solubility limits. Maximum concentrations of the other radionuclides are limited by their inventories, which are too low to reach solubility limits. Regarding corrosion of cemented waste forms and the backfill material in MgCl2 rich brines, experimental data and calculated results agree well. Experimental results demonstrate the ability of the Mg(OH)2-based material to buffer the pH and to limit the HCO3− / CO32− concentration in the brines. Based on both the modeling and the experimental results, it is highly recommended to apply the Mg(OH)2-based backfill material in the Asse salt mine.

The Solid Waste Disposal Authority of Palm Beach County owns a municipal waste-to-energy plant located in West Palm Beach, Florida. Currently, ash generated by the operation of the facility is disposed at the Authority’s adjacent Class I Landfill. In 1998, the Florida Legislature amended certain provisions of the Florida Statutes to encourage the beneficial reuse of municipal waste-to-energy ash in manners that are protective of human health and the environment. To that end, the Florida Department of Environmental Protection developed a document entitled “Guidance for Preparing Municipal Waste-to-Energy Ash Beneficial Use Demonstrations” to assist communities in developing reuse demonstrations. SWA and CDM undertook a project and developed a report in accordance with the Guidance document to demonstrate that reuse of the ash from the SWA’s waste-to-energy facility as a landfill construction material is consistent with the reuse goals set forth by the Legislature. Initial studies were performed to identify locations and quantities for use of ash within the confines of SWA property. Some of these locations included future Class I and Class III Landfill cells and perimeter roadways. It was determined that nearly 3 million cubic yards of landfill space could be saved through beneficial reuse of the ash. An initial analytical screening was performed to test the leaching potential of the eight RCRA metals and compare to applicable groundwater and surface water standards. Overall results were favorable, with some indication that lead could pose potential concern. Geotechnical index testing (grain size, moisture content, and organic content) was performed to determine if ash has similar physical properties to the sand that is currently used on-site. Results indicated that the ash has similar physical properties to the sandy material. This initial testing was performed in accordance with the July 1998 DRAFT version of the guidance document.

One of the important parameters in the reduction of greenhouse gas emission can be considered as the energy efficiency of the building. The building sector is constantly innovating in its use of materials with regards to sustainability. There is a need to use cost-effective, environmentally friendly materials and technologies which lessen the impact of a construction in terms of its use of non-renewable resources and energy consumption. For the reduction in energy consumption, thermally insulating materials can be installed inside the building envelope. It prevents heat loss and provides thermal comfort for the occupants. The introduction of the organic waste materials for thermal insulation is recent and little is known for their environmental effect in comparison with the conventional materials. Present study consists of experimental analysis to investigate the composition of wood powder and ash brick as a brick. Different modifications have been performed to determine the best methodology for the change in standard ash brick. The study has been concluded with the help of heat transmission factor and compressive strength.

Nowadays one of the main tasks of environmental protection is the management and recycling of plastic waste. Plastic occupy the major part of all public waste and with this material is polluted all earth. In natural condition plastic decompose in 400 or even in 500 years. Therefore, it is important to solve this problem reusing plastic waste. One of the possible areas is construction industry. In the present paper were estimated how plastic waste impact the properties of concrete. During the research the part of coarse aggregates were changed with polyethylene (PE) pellets and cut polypropylene (PP) particles. The change of fresh concrete density, workability and hardened concrete density, compression strength, water absorbability were evaluated. The results show, that plastic waste has a positive effect on fresh concrete properties: the concrete become more workable and lighter. Unfortunately, on the main hardened concrete properties the increase plastic waste amount has the negative effect: the compression strength was decreasing and the water absorbability was increasing. However, generalizing all results, can be stated, that keeping the same level of concrete workability there are possibilities to reduce water and cement ratio and it will give strength loss and water absorbability growth compensation.