Technology selection and process development for enhancing water recovery from mine tailing water: A case study

Among generic technology management activities, rapid technology identification and selection stand as the significant determinants of technology adoption success in the digital transformation era. Especially for manufacturing SMEs in developing countries, rapid digital technologies are critical since they struggle to protect their competitiveness in global value chains threatened by digitalization. Previous studies introduce various multi-criteria decision-making model-based approaches to identify and select appropriate manufacturing technologies. However, these approaches were relatively rigid and required an advanced understanding of the technology for criteria and alternative settings and evaluation. Decision-makers need more flexible and scalable contextual frameworks for technology selection in digitalization. Since digital technologies offer both benefits and challenges, the decision-making models should reflect this dialectic nature of Industry 4.0 adoption and contextually optimize their decisions by combining multiple quantitative methods for technology identification and selection. Besides, case studies on digital technology selection are rare in manufacturing SMEs from developing country context in the literature. In this context, this study proposes a technology selection framework that utilizes the three dimensions (industry 4.0 technologies, benefits, and challenges) and combines AHP with a QFD-inspired intervention matrix and an optimization model by Mixed Integer Programming (MIP). The proposed model is validated with a case study from the automotive supplier industry in Turkey with the data provided from interviews and a Delphi survey with 11 experts from the digitalization value chain of the selected industry. Case study results revealed that the highest benefits of industry 4.0 lie in process/quality efficiency improvement and reduced inventory. At the same time, data analytics and sensor technologies occurred as the most critical tools. Significant challenges of digital technology adoption are insufficient expert know-how and budget constraints.

Using the lamination process in the high-functionality textile industry, this paper investigates the development of an approach for technology and supplier selection based on 12 factors affecting manufacturing technology selection with respect to the supply chain. In many manufacturing industries, technology selection still represents a challenging and not fully understood area, especially when it comes to choosing between competing technologies with similar levels of performance. The methodology employed identified two competing lamination technologies with high levels of development and mechanization: 1) full lamination/solvent type; and 2) dot lamination/solvent free. This was followed by the identification of multiple factors affecting manufacturing technology selection with respect to the supply chain, the use of analytical hierarchy process techniques, and a case study involving site visits and interviews with the senior management of a company operating in the high-functionality textiles industry. The analysis of empirical data gathered from the case study revealed how supply chain related factors are more important than those directly related to the technical merit of the technology such as low-cost manufacturing or automation. The proposed approach has the potential to be transferable to other industries using lamination processes and/or advanced fiber and fabric technology.

Techniques were developed to assess the probable cumulative impacts of anticipated surface mining upon the hydrology of and area. An activity profile of cumulative drainage area versus river miles downstream from the surface mining site is constructed that shows major water uses, flood prone areas, and stream classifications. From the summary shown by the activity profile, an impact matrix is used as a checklist for the importance of the impacts under categories such as water supply, flood prone areas, water contact recreation, etc. Based on the categories checked on the impact matrix, a simple, less accurate model or a more comprehensive and accurate one can be used to quantify the impacts. Quantified impacts are then displayed on an impact profile showing the percentage change in a hydrologic characteristic versus distance downstream of the surface mining site. The simple model for quantification considers only dilution from tributary areas during critical periods whereas the comprehensive model routes flows and quality of water continuously through the year and considers, in addition to dilution, instream processes such as settling, biological uptake , and chemical reactions. (USGS)

Closure of mining landscapes is widely discussed within, and investigated by, the mining industry with increasingly innovative alternative uses found for open pits, underground workings, waste rock landforms, tailings storage facilities and water dams. When it comes to industrial and ancillary infrastructure though, many mining companies elect only to decommission and dispose of this infrastructure onsite. However, there is a growing need for efficient, effective and sustainable ways to find alternative purposes for these features, particularly in the face of increasing resource scarcity. The concept of ‘adaptive re-use’ is not new: it is common in the construction industry where re-use of materials and equipment is considered to be a win-win strategy, in modern communities, where recycling and even upcycling has become second nature, and in urban renewal, where there is a focus on repurposing of heritage buildings and other structures. Further, there is growing support for the ‘circular economy’ ethos, which favours careful management of resources and intelligent re-use of products and reconsidering the term ‘market’ more broadly. Many mining companies are now adopting a circular approach in selected areas of their business and while this is mainly focused on active operations, it is considered that there is an opportunity to extend this thinking to mine closure. However, identifying what materials can be ‘mined’ for re-use or repurposing can be challenging, partly due to obsolescence but also because of tenure restrictions, liability issues, transport costs, legal constraints and other factors. On this basis, the ‘5R Model’ has been developed to facilitate decision-making in relation to the alternative uses for industrial and ancillary infrastructure associated with mining and mineral processing operations. This paper outlines the basis of the 5R Model and the way in which this classification system can be used to guide investigations and decision-making for repurposing of industrial and ancillary infrastructure, including blue-sky options. Drawing on case studies on alternative closure scenarios for mining and mineral processing infrastructure and lessons learned from ‘urban mining’, this paper also discusses potential pathways to achieve these uses and facilitate custodial transfer of physical assets, and ways in which this model can also assist companies meet their waste minimisation, carbon reduction and other targets during closure of their sites.

One of the main challenges in technology transfer (TT) process is technology selection. Even though there are many researches that have focused on the technology selection, however technology selection remains a sensitive activity in technology management which there has not been much attention toward it by managers and scholars. Defining the position of technology selection in the technology transfer process, and considering technology selection through perspectives of technology management and a decision making problem, this paper presents a framework based on five professional workshops. In the mentioned framework, five technology selection criteria namely technological, technical, organisational capability, peripheral environment and supplier are identified and extracted by the exploratory factor analysis method. A real problem in automotive industry is also solved by using fuzzy TOPSIS method to explain how the framework is applied.

Nowadays, one of the most significant problems in mining activities is the significance of analyzing environmental issues along with mining, concentration, and mineral processing operations to achieve the goals of sustainable development. Nevertheless, mine owners refuse to include environmental costs (EC) and consider them unprofitable. Due to the ever-increasing importance of environmental and social topics in recent years, there is a vital need for assessing the EC and its impact on total mining costs and implementing green strategies by the mining managers and engineers. The current study tries to model the mining cost structure by considering the causal relationships between different factors affecting open-pit mining costs to highlight the EC’s role. Furthermore, this research evaluates the effectiveness of implementing each possible mining green strategy in a large-scale copper mine using the System Dynamics (SD) approach. In this regard, seven scenarios and a combination of different environmental strategies, including mine reclamation, an environmental strategy for a condensation and processing plant, and environmental mining operations, have been considered for the SD-based economic analysis. The simultaneous use of the green mining strategies for the concentration and processing plant (Scenario 4) shows a high impact on cost reduction in the mining operation.

1. The method of removing the excess of hydrobromic acid after it has had a chance to react chemically with gelatin has permitted us to measure the amount of Br in combination with the gelatin. It is shown that the curves representing the amount of bromine bound by the gelatin are approximately parallel with the curves for the osmotic pressure, the viscosity, and swelling of the gelatin solution. This proves that the curves for osmotic pressure are an unequivocal function of the number of gelatin bromide molecules formed under the influence of the acid. The cc. of 0.01 N Br in combination with 0.25 gm, of gelatin we call the bromine number. 2. The explanation of this influence of the acid on the physical properties of gelatin is based on the fact that gelatin is an amphoteric electrolyte, which at its isoelectric point is but sparingly soluble in water, while its transformation into a salt with a univalent anion like gelatin Br makes it soluble. The curve for the bromine number thus becomes at the same time the numerical expression for the number of gelatin molecules rendered soluble, and hence the curve for osmotic pressure must of necessity be parallel to the curve for the bromine number. 3. Volumetric analysis shows that gelatin treated previously with HBr is free from Br at the isoelectric point as well as on the more alkaline side from the isoelectric point (pH ≧ 4.7) of gelatin. This is in harmony with the fact that gelatin (like any other amphoteric electrolyte) can dissociate on the alkaline side of its isoelectric point only as an anion. On the more acid side from the isoelectric point gelatin is found to be in combination with Br and the Br number rises with the pH. 4. When we titrate gelatin, treated previously with HBr but possessing a pH = 4,7, with NaOH we find that 25 cc. of a 1 per cent solution of isoelectric gelatin require about 5.25 to 5.5 cc. of 0.01 N NaOH for neutralization (with phenolphthalein as an indicator). This value which was found invariably is therefore a constant which we designate as "NaOH (isoelectric)." When we titrate 0.25 gm. of gelatin previously treated with HBr but possessing a pH < 4.7 more than 5.5 cc. of 0.01 N NaOH are required for neutralization. We will designate this value of NaOH as "(NaOH)n," where n represents the value of pH. If we designate the bromine number for the same pH as "Brn" then we can show that the following equation is generally true: (NaOH)n = NaOH (isoelectric) + Brn. In other words, titration with NaOH of gelatin (previously treated with HBr) and being on the acid side of its isoelectric point results in the neutralization of the pure gelatin (NaOH isoelectric) with NaOH and besides in the neutralization of the HBr in combination with the gelatin. This HBr is set free as soon as through the addition of the NaOH the pH of the gelatin solution becomes equal to 4.7. 5. A comparison between the pH values and the bromine numbers found shows that over 90 per cent of the bromine or HBr found was in our experiments in combination with the gelatin.

This research aims at developing a decision-making strategy for instituting and integrating renewable energy technologies into the mining operations in order to achieve sustainable development. The current mining operations, depending mainly on energies from fossil fuels, have created unsustainable environmental degradation and social inequality. Mining operations consume 38% of energies in the industrial sector resulting in huge amounts of greenhouse gases (GHG) emissions. The urgency to transition to “inclusive green economy” has never been critical as now as nations are making attempts to greening their economies in order to achieve UN Agenda 2030 for Sustainable Development. The methodologies used included review of existing literature, analysis of data from previous studies, review of case studies and obtaining expert opinions on the subject matter from key stakeholders. The study adopted qualitative methods in obtaining data from primary sources through well-structured questionnaires to identify the strengths, weaknesses, opportunities and threats (SWOT) for using renewable energy in operations of Newmont Ghana. The Quantitative Strategic Planning Method (QSPM) was adopted to quantify the qualitative results from SWOT analysis. The key strategic internal and external factors were identified to design a suitable strategic option for incorporating renewable energy technologies into mining operations at Newmont Ghana. The weighted sum of strategic internal factors (WSSIF) and the weighted sum of strategic external factors (WSSEF) were calculated and results presented in four quadrants, each representing different strategic approaches. The study identified that it is viable to integrate renewable energy in mining operations of Newmont Ghana as the WSSIF and WSSEF are all positive and greater than the mean score. Based on the results the aggressive strategy is the appropriate strategy to adopt by Newmont Ghana to integrate renewable energy in its operations. Thus, all the strengths of renewable energy technology the Company possesses must be harnessed and utilized to benefit from conducive factors available in the external environment to incorporate renewable energy technologies in the operations of mines. The study provides a decision-making tool that can be applied by organizations whenever they want to evaluate or embark on innovative projects, based on their internal and external strategic factors.

The swelling of the chloroplasts of NiteUa cristata A. Br. in solutions of different osmotic pressures has been examined in relation to their fine structure, isoelectric point, and permeability towards KCl.

Measurements have been made at 40°C. of the osmotic pressure and viscosity of 1 per cent gelatin solutions containing varying amounts of hydrochloric acid or sodium hydroxide. Each property was found to exhibit a decided minimum near pH 4.7. In the osmotic pressure experiments the pH of the inside solutions was greater than that of the outside solutions at pH values below 4.7, while it was less than that of the outside solutions at values above pH 4.7. These results indicate that gelatin at 40°C. retains its isoelectric point at about pH 4.7.

Evaluation of groundwater hydrochemical characteristics and mixing behavior in the Daying and Qicun geothermal systems, Xinzhou Basin

The aim of this paper is to present an experience of coarse sediment drawdown flushing tests carried out in a reduced scale model for Palomino Hydroelectric Project (Dominican Republic). It characterizes the volume of reservoir recovered over time after the opening of the bottom outlet gate. Tests were performed with a movable bed composed by non-cohesive graded material. Its gradation was controlled according to the Froude similarity in term of the shear stresses that cause the entrainment according to Shields criterion. The purged volume was measured by the sediment concentration of released discharge and by the topographic measurement in the reservoir and both results achieved similar values. The model tests proved to be highly appropriate for showing the region where the volume recovery is more intense, i.e. whether flushing is really useful for the reservoir.

This review paper focuses on the use of iron oxide nanocomposites for the removal of hexavalent chromium, Cr(VI), from wastewater. Cr(VI) is very toxic and carcinogenic as compared to Cr(III) and can cause health defects such as liver, lung and kidney damage. It is mostly expelled from untreated or partially treated effluents from mining operation, electroplating and water cooling activities. As a result, these activities produce effluents with higher concentration levels of Cr(VI) than the acceptable discharge limits of 0.1 and 0.05 mg/L in inland surface water and drinking water, respectively, as regulated by the World Health Organisation (WHO). This review paper summarises the performance of different water treatment technologies studied on the last decade. Adsorption technology has emerged as an attractive method for Cr(VI) removal from industrial wastewater amongst the mentioned methods. Hence, the adsorption isotherms and kinetics models are also discussed in this review paper. The factors such as the effect of solution pH, temperature, initial Cr(VI) concentration, adsorbent dosage and other coexisting ions are also briefly discussed. In this review, magnetic polymers reveal good result than other techniques used in water treatment because of its high surface area (surface/volume ratio). It is suggested that these may be used in the future at large-scale water purification. It is also found that the polymer rich with amino groups (polypyrrole and polyaniline) enhanced Cr (VI) removal efficiency. From the results, it is evident that more attention needs to be paid on the industrial application of the technologies which were successful in the laboratory scale. In the future, combination of both copolymers may be the best option for treatment of wastewater.

Physical aging is currently a major obstacle for the commercialization of PIM-1 membranes for gas separation applications. A well-known approach to reversing physical aging effects of PIM-1 membranes at laboratory scale is soaking them in lower alcohols, such as methanol and ethanol. However, this procedure does not seem applicable at industrial level, and other strategies must be investigated. In this work, a regeneration method with alcohol vapors (ethanol or methanol) was developed to recover permeability of aged PIM-1 membranes, in comparison with the conventional soaking-in-liquid approach. The gas permeability and separation performance, before and post the regeneration methods, were assessed using a binary mixture of CO2 and CH4 (1:1, v:v). Our results show that an 8-hour methanol vapor treatment was sufficient to recover the original gas permeability, reaching a CO2 permeability > 7000 barrer.

Clays can act as osmotic membranes and thus give rise to osmotically induced hydrostatic pressures. The magnitude of generated osmotic pressures in geologic systems is governed by the theoretical osmotic pressure calculated solely from solution properties and by value of the membrane's three phe-nomenological coefficients: the hydraulic permeability coefficient, Lp; the reflection coefficient, σ; and the solute permeability coefficient, ω. Generally, low values of Lp correspond to highly compacted membranes in which σ is near unity and ω approaches zero. Such membrane systems should give rise to initially high osmotic fluxes and gradual dissipation of their osmotic potentials.The high fluid pressures in the Dunbarton Triassic basin, South Carolina, are a good example of osmotically induced potentials. A unique osmotic cell is created by the juxtaposition of fresh water in the overlying Cretaceous sediments against the saline pore water housed within the membrane-functioning sediments of the Triassic basin. Because wells penetrating the saline core of the basin show anomalously high heads relative to wells penetrating the basin margins, the longevity of this osmotic cell is probably dictated by the rate at which salt diffuses out into the overlying fresh water aquifer.