Mineral Resource Scarcity Research Articles

Life cycle analysis of a biorefinery for activated carbon and biomethane production

A Life Cycle Analysis (LCA) based on ReCiPe 2016 model of a biorefinery case-study was performed. On the basis of an existing Portuguese Anaerobic Digestion plant, the proposed biorefinery hypothesized the use of (i) Maize Cob Waste (MCW) as co-substrate for Anaerobic co-Digestion (AcoD) with Organic Fraction Municipal Solid Waste (OFMSW), (ii) the use of MCW derived activated carbons (ACs) in a H2S removal unit, and (iii) the biogas upgrading to biomethane in a Pressure Swing Adsorption unit. The main aim was to compare the environmental benefits obtained from distinct uses of biogas, specifically the cogeneration of electricity/heat and biomethane production.Three biogas production configurations were considered: (i) AD of standalone hydrolysed OFMSW (hOFMSW); (ii) AcoD of hOFMSW and MCW pre-treated with H2O2 (hOFMSW + PreMCW); and (iii) AcoD of hOFMSW with non-pre-treated MCW (hOFMSW + MCW). The increase of biogas and methane yields obtained with AcoD of hOFMSW + MCW provided an overall better environmental performance than other configurations. With this configuration the FRS, MRS and GW (hh) categories of impacts provided values of 3.12E-02 and -2.49E-05 US$2013, and 4.87E-09 DALY, respectively, that are 47%, 15% and 97% lower than the corresponding value obtained with AD of standalone OFMSW.The biogas upgrading to biomethane from AcoD of hOFMSW + MCW generated higher environmental impacts than cogeneration, due to the AC production and upgrading processes. If an optimised H2S adsorption capacity is considered, the Fossil Resource Scarcity, Mineral Resource Scarcity, and Global Warming human health impact categories decreased by 20%, 15%, and 17%, respectively, when compared to the base-case upgrading scenario. Further decreases of up to 52%, 23%, and 28% for those impact categories, respectively, are observed when the natural gas used in the OFMSW collection and transportation fleet is substituted by biomethane produced in the biorefinery.

Environmental impact assessment of organic fraction of municipal solid waste treatment by anaerobic digestion in Sri Lanka.

The management of organic fraction of municipal solid waste (OFMSW) has continued to be a significant challenge in Sri Lanka. Anaerobic digestion is one of the management options of OFMSW. However, it generates unavoidable environmental impacts that should be addressed. The present study focuses to assess the environmental impact of a full-scale anaerobic digestion plant in Sri Lanka from a life cycle perspective. The inventory data were obtained from direct interviews and field measurements. Environmental burdens were found to be in terms of global warming potential (230 kg CO2 eq) ozone formation on human health (6.15 × 10-6 kg NOx eq), freshwater eutrophication (2.92 × 10-3 kg P eq), freshwater ecotoxicity (9.27 × 10-5 kg 1,4 DCB eq), human carcinogenic toxicity (3.98 × 10-4 kg 1,4 DCB eq), land use (1.32 × 10-4 m2 a crop eq) and water consumption (2.23 × 10-2 m3). The stratospheric ozone depletion, fine particulate matter formation, ozone formation on terrestrial ecosystems, terrestrial acidification, marine eutrophication, ecotoxicity (terrestrial and marine), human non-carcinogenic toxicity, mineral resource scarcity and fossil resource scarcity, were avoided due to electricity production. Results show that the direct gaseous emissions and digestate generation should be addressed in order to reduce the burdens from the anaerobic digestion plant. Finally, the results of the study could help in policy formation and decision-making in selecting future waste management systems in Sri Lanka.

Scarce mineral resources: Extraction, consumption and limits of sustainability

The interests of the current and future generations concerning the access to and the use of geologically scarce mineral resources diverge. This article explores whether this apparent irreconcilability can be resolved. It is investigated how far the extraction rate of thirteen scarce raw materials can be reduced while simultaneously increasing the services they provide worldwide to the level prevailing in developed countries in 2020. The scarce raw materials considered are antimony, bismuth, boron, chromium, copper, gold, indium, molybdenum, nickel, silver, tin, tungsten, and zinc. Indicative estimates of how long these mineral resources will be available for humanity are calculated, assuming (1)the world population stabilizes at ten billion people, (2) the global service level of these resources attains that prevailing in developed countries in 2020 and (3) maximum resource-saving measures are taken. The conclusion is that immediate implementation of the most stringent resource-saving measures could extend the estimated exhaustion periods of most of the scarcest raw materials by an average factor of approximately four, even while simultaneously increasing the global service level of these resources by a factor four as well. Without sufficient and adequate resource saving measures it will be difficult or impossible for a substantial part of the future world population to attain the service level of mineral resources prevailing in developed countries at this moment. Moreover, without such measures, the period of time that future citizens of rich countries can continue enjoying the current service level of some of the scarcest mineral resources in their countries, will be severely limited.

Life Cycle Assessment of Households in Santiago, Chile: Environmental Hotspots and Policy Analysis

The aim of this study is to assess the environmental impacts of household life cycles in Santiago, Chile, by household income level. The assessment considered scenarios associated with environmental policies. The life cycle assessment was cradle-to-grave, and the functional unit considered all the materials and energy required to meet an inhabitant’s needs for one year (1 inh/year). Using SimaPro 9.1 software, the Recipe Midpoint (H) methodology was used. The impact categories selected were global warming, fine particulate matter formation, terrestrial acidification, freshwater eutrophication, freshwater ecotoxicity, mineral resource scarcity, and fossil resource scarcity. The inventory was carried out through the application of 300 household surveys and secondary information. The main environmental sources of households were determined to be food consumption, transport, and electricity. Food consumption is the main source, responsible for 33% of the environmental impacts on global warming, 69% on terrestrial acidification, and 29% on freshwater eutrophication. The second most crucial environmental hotspot is private transport, whose contribution to environmental impact increases as household income rises, while public transport impact increases in the opposite direction. In this sense, both positive and negative environmental effects can be generated by policies. Therefore, life-cycle environmental impacts, the synergy between policies, and households’ socio-economic characteristics must be considered in public policy planning and consumer decisions.

Upgrading wineries to biorefineries within a Circular Economy perspective: An Italian case study

In the challenge of transforming waste into useful products that can be re-used in a circular perspective, Italian wine industry can represent a suitable model for the application of the bioeconomy principles, including the valorisation of the agricultural and food waste. In the present study, a comprehensive environmental assessment of the traditional production of wine was performed and the potentiality of a biorefinery system, based on winery waste and aimed at recovering useful bio-based products, such as grapeseed oil and calcium tartrate, was examined through Life Cycle Assessment (LCA). The wine company “I Borboni”, producing Asprinio wine in the Campania Region (Italy), was proposed as a case study. The hotspots of the linear production system were identified and the bottling phase, in particular the production of packaging glass, resulted to contribute to the generation of impacts at 63%, on average, versus 14.3% of the agricultural phase and 22.7% of the vinification phase. The LCA results indicated human carcinogenic toxicity, freshwater eutrophication and fossil resource scarcity impact categories as the most affected ones, with normalized impacts amounting to 9.22E−03, 3.89E−04 and 2.64E−04, respectively. Two side production chains (grapeseed oil and tartrate production) were included and circular patterns were designed and introduced in the traditional production chain with the aim of valorising the winery residues and improving the overall environmental performance. By implementing the circular approach, environmental impacts in the global warming, freshwater eutrophication and mineral resource scarcity impact categories, in particular, resulted three times lower than in the linear system. The results achieved demonstrated that closing the loops in the wine industry, through the reuse of bio-based residues alternatively to fossil-based inputs within the production process, and integrating the traditional production system with new side production chains led to an upgrade of the wineries to biorefineries, towards more sustainable production patterns.

Life Cycle Analysis of a Biorefinery for Activated Carbon and Biomethane Production

A Life Cycle Analysis (LCA) based on ReCiPe 2016 model of a biorefinery case-study was performed. On the basis of an existing Portuguese Anaerobic Digestion plant, the proposed biorefinery hypothesized the use of (i) Maize Cob Waste (MCW) as co-substrate for Anaerobic co-Digestion (AcoD) with Organic Fraction Municipal Solid Waste (OFMSW), (ii) the use of MCW derived activated carbons (ACs) in a H2S removal unit, and (iii) the biogas upgrading to biomethane in a Pressure Swing Adsorption unit. The main aim was to compare the environmental benefits obtained from distinct uses of biogas, specifically the cogeneration of electricity/heat and biomethane production.Three biogas production configurations were considered: (i) AD of standalone hydrolysed OFMSW (hOFMSW); (ii) AcoD of hOFMSW and MCW pre-treated with H2O2 (hOFMSW+PreMCW); and (iii) AcoD of hOFMSW with non-pre-treated MCW (hOFMSW+MCW). The increase of biogas and methane yields obtained with AcoD of hOFMSW+MCW provided an overall better environmental performance than other configurations.The biogas upgrading to biomethane from AcoD of hOFMSW+MCW generated higher environmental impacts than cogeneration, due to the AC production and upgrading processes. If an optimised H2S adsorption capacity is considered, the Fossil Resource Scarcity, Mineral Resource Scarcity, and Global Warming human health impact categories decreased by 20%, 15%, and 17%, respectively, when compared to the base-case upgrading scenario. Further decreases of up to 52%, 23%, and 28% for those impact categories, respectively, are observed when the natural gas used in the OFMSW collection and transportation fleet is substituted by biomethane produced in the biorefinery.

Application of fuzzy recognition method in mineral resources allocation

In order to provide a basis for the development of mineral resources and the implementation of spatial zoning management, the application of fuzzy recognition method in mineral resources allocation is studied and analyzed in this study to promote the optimal allocation of mineral resources and establish a reasonable regional division of labor and cooperation relationship. The results show that, taking the suitability of mineral resources spatial development as the evaluation objective, on the basis of the analysis of influencing factors and mechanism of mineral resources development, the index system, index calculation method, regionalization discriminant system and matrix discriminant model for the functional regionalization of mineral resources development are constructed, which has important reference value for promoting the system of optimum allocation of mineral resources. From the comprehensive perspective of quantity, quality, and concentration of resources, a set of comprehensive evaluation indexes and calculation methods reflecting the basic conditions of regional mineral resources (resource abundance) are proposed. Through empirical research, the index system and method of functional zoning of mineral resources development are verified, and the development function zoning scheme of main solid mineral resources in China is put forward. The results can provide macro decision-making reference for guiding mineral resources exploration, development, utilization and protection according to local conditions, zoning planning, and classification. This suggests that the limited and relatively scarce mineral resources are rationally allocated in order to produce the most suitable commodities and services and obtain the best benefits with the least resource consumption.

What Does It Take to Go Net-zero-CO2? A Life Cycle Assessment on Long-term Storage of Intermittent Renewables With Chemical Energy Carriers

The concept of net-zero-CO2 power systems has gained increased attention by the EU goal to be a climate neutral continent by 2050. As potential pathways towards a net-zero-power system, this work analyzes future power systems based on intermittent renewable electricity with long-term storage through chemical energy carriers, so called Power-to-Fuel-to-Power systems, and a system based on the combustion of natural gas with 100% carbon capture and storage. The chemical energy carriers selected for electricity storage are hydrogen, methane and ammonia. Using life cycle assessment, we determine and compare the environmental impacts of 1 kWh of dispatchable electricity produced by the two pathways on seven impact categories. There was not one single pathway that had the most environmental benefits on all seven impact categories. Of the Power-to-Fuel-to-Power systems assessed the use of hydrogen for storage has the lowest environmental impact in all categories. Additionally, all the Power-to-Fuel-to-Power systems have a lower environmental impact on climate change, photochemical ozone formation and fossil resource depletion compared with the natural gas with carbon capture and storage system. The natural gas with carbon capture and storage system has a lower environmental impact on particulate matter formation, marine eutrophication and mineral resource scarcity. Our work is complemented by an analysis of pathways from a net-zero-direct-CO2 to a life-cycle net-zero-CO2-equivalent power system which is actually climate neutral, achieved by direct air capture of the residual CO2 from the atmosphere. However, this leads to an increase in all other impact categories of 11% for the Power-to-Fuel-to-Power systems and 21% in the natural gas combustion with carbon capture and storage system. A system sizing study also highlights the very low capacity factors of the capital employed for electricity storage, raising the point of economic feasibility.

Life cycle assessment of shallow to medium-depth geothermal heating and cooling networks in the State of Geneva

Geothermal heating and cooling from a depth of 10–3′500 meters have considerable decarbonization potential but understudied life-cycle environmental impacts. We quantified the life-cycle impacts of six heating and cooling configurations from shallow to medium-depth geothermal wells with connected, decentralized heat pumps and district heating and cooling in the State of Geneva. Shallower systems with connected heat pumps have better environmental performance than systems with district heating, whereas shallow systems with free cooling perform best for cooling. These environmental impacts are lower than those of fossil fuels, except for mineral resource scarcity, especially with decentralized heat pumps and free cooling.

Are the electric vehicles more sustainable than the conventional ones? Influences of the assumptions and modeling approaches in the case of typical cars in China

In order to make the sustainable development of transport system, China has taken actions toward the electrification transition of vehicles. However, whether the electric vehicles (EVs) are more environmentally friendly than the conventional internal combustion engine vehicles (ICEVs) in China is still not clear due to a lack of complete and consistent environmental impact comparison of vehicles. This study takes the vehicle models from BYD Qin Pro series in China as illustrations to compare the environmental impact of battery electric vehicle (BEV) and plug-in hybrid electric vehicle (PHEV) with the conventional ICEV. The environmental profiles of vehicles across the whole life cycle within a set of environmental indicators are analyzed. The key aspects that may heavily influence the environmental impacts, i.e. regional heterogeneity, technology improvement and different modeling methods (attributional vs consequential) choices, are further tested, respectively. The results show that already today the BEV and PHEV powered by the current average Chinese electricity mix offer 23% and 17% reduction of global warming potential (GWP), respectively, compared to the gasoline ICEV. But it is achieved at the expense of considerable increases in mineral resource scarcity and ecological and human toxicity, etc. All of the factors considered show markedly influences on the environmental profiles of EVs, even up to 51% of GWP differences for different modeling methods application. And they all have the possibility to reverse the environmental priorities of some impact categories among ICEV, BEV and PHEV.

What Does It Take to Go Net-Zero-CO2? A Life Cycle Assessment on Long-Term Storage of Intermittent Renewables With Chemical Energy Carriers

The concept of net-zero-CO2 power systems has gained increased attention by the EU goal to be a climate neutral continent by 2050. As potential pathways towards a net-zero-power system, this work analyzes future power systems based on intermittent renewable electricity with long-term storage through chemical energy carriers, so called Power-to-Fuel-to-Power systems, and a system based on the combustion of natural gas with 100% carbon capture and storage. The chemical energy carriers selected for electricity storage are hydrogen, methane and ammonia. Using life cycle assessment, we determine and compare the environmental impacts of 1 kWh of dispatchable electricity produced by the two pathways on seven impact categories. There was not one single pathway that had the most environmental benefits on all seven impact categories. Of the Power-to-Fuel-to-Power systems assessed the use of hydrogen for storage has the lowest environmental impact in all categories. Additionally, all the Power-to-Fuel-to-Power systems have a lower environmental impact on climate change, photochemical ozone formation and fossil resource depletion compared with the natural gas with carbon capture and storage system. The natural gas with carbon capture and storage system has a lower environmental impact on particulate matter formation, marine eutrophication and mineral resource scarcity. Our work is complemented by an analysis of pathways from a net-zero-direct-CO2 to a life-cycle net-zero-CO2-equivalent power system which is actually climate neutral, achieved by direct air capture of the residual CO2 from the atmosphere. However, this leads to an increase in all other impact categories of 11% for the Power-to-Fuel-to-Power systems and 21% in the natural gas combustion with carbon capture and storage system. A system sizing study also highlights the very low capacity factors of the capital employed for electricity storage, raising the point of economic feasibility.

Primary data priorities for the life cycle inventory of construction products: focus on foreground processes

Life cycle assessment can support decisions for improving the environmental performance of construction products. However, the amount of data required for developing life cycle inventories limits the adoption of LCA. This work associates the interpretation of the impact results of construction products at the unit process level with a quantitative definition for the foreground and background system, for guiding primary data collection towards foreground processes that can be affected by decision-makers in the construction sector. A set of construction products commonly used in Brazil is selected, and their cradle-to-gate life cycle inventories are modeled using the ecoinvent database (version 2). Life cycle impact assessment is performed using the ReCiPe Midpoint Hierarchist method. The contribution of each process during the life cycle of construction products for each impact category is quantified. These processes are associated with economic sectors, which are classified as belonging to the foreground or background system from the perspective of the construction industry. Foreground sectors are those controlled or influenced by the construction sector and are defined based on the production share consumed by the construction value chain. The elementary flows defining each impact category are also identified. Foreground processes show significant contributions to most impact results of construction products. Global warming, fine particulate matter formation, ozone formation, acidification, human carcinogenic toxicity, and terrestrial ecotoxicity are mainly caused by direct emissions and fossil fuel combustion in manufacturing processes. Land occupation for production activities contributes to land use change, while the consumption of fuels, raw materials, and water causes fossil and mineral resource scarcity and water consumption respectively. Freshwater and marine ecotoxicities and human non-carcinogenic toxicity have foreground contributions only for steel and copper products due to emissions from the landfilling of mining tails. Ionizing radiation and stratospheric ozone depletion are mostly driven by background processes. A reduced group of elementary flows covers a big share of the environmental impacts of most construction products. The results indicate priorities for life cycle inventory primary data collection of construction products, by focusing on foreground processes and the corresponding elementary flows that cause many of the potential embodied impacts of construction. Increasing the availability of primary data for these processes improves the reliability of LCA-based decisions in the construction sector, especially in countries which still lack local LCI databases.

Sustainable management of spent fluid catalytic cracking catalyst from a circular economy approach

For sustainable growth, an economic model must tend toward a circular system, especially in the field of waste management. This work focuses on the valorization of spent fluid catalytic cracking catalyst from oil refineries, which generate 400,000 metric tons of spent catalyst per year worldwide, most of which is sent to landfills. A new alternative to landfilling is proposed for this waste, based on the combination of acid leaching for the recovery of lanthanum, a valuable rare earth, and the reuse of the leached solid residue as a cement substitute. A comparative life cycle assessment was made, including four environmental impact categories, i.e. global warming, fossil resource scarcity, mineral resource scarcity and water consumption, in order to quantify the potential environmental benefits of secondary lanthanum recovery from industrial waste with respect to primary lanthanum extraction from mineral resources. A maximum of 85.6% La recovery was achieved and 15 wt% of cement can be substituted with leached solid residue without changing the original cement classification. The waste management process presented in this paper promotes the sustainable management of the spent fluid catalytic cracking catalyst and contributes to the development of a new resource for a critical material such as lanthanum. The implementation of this novel waste management process could reduce global warming and mineral resource scarcity but would increase fossil resource scarcity and water consumption in comparison with primary La extraction.

Comparative life cycle assessment of lithium-ion battery chemistries for residential storage

Residential storage deployment is expected to grow dramatically over the coming decade. Several lithium-ion chemistries are employed, but the relative environmental impacts of manufacturing them is poorly understood. This study presents a cradle-to-gate life cycle assessment to quantify the environmental impact of five prominent lithium-ion chemistries, based on the specifications of 73 commercially-available battery modules used for residential applications. Three impact categories (global warming potential, cumulative energy demand and mineral resource scarcity) are analysed across two functional units (storage capacity and lifetime energy delivered). Most chemistries have embodied carbon footprints of around 200 kg CO2e per kWh of useable storage capacity, which corresponds to 43–84 g CO2e per kWh of lifetime energy delivered with daily cycling operation. Energy delivered on energy invested is also calculated at values of 2–4, which falls to 0.54–0.66 with the energy for charging included (cf. a round-trip efficiency of 82–89%). Environmental impact depends more on cycling frequency than chemistry choice, and none of the battery chemistries convincingly outperforms the others. Cells only constitute a third to a half of the environmental impact, which is comparable to the inverter. Routes to making residential lithium-ion battery systems more environmentally benign include reducing the reliance on cobalt, nickel and copper, increasing the specific useable energy, developing comprehensive recycling initiatives, and maximising the utilisation (cycle frequency) once in operation.

Comparative life cycle assessment of byproducts from sugarcane industry in Pakistan based on biorefinery concept

A comparative life cycle assessment of the sugarcane biorefinery in different conceptual arrangements was conducted considering four different alternatives with increasing utilization of byproducts. The first alternative with the least use of byproducts was taken as the base case and the fourth alternative was a completely integrated plant with gradually enhanced and efficient use of byproducts. The functional unit was defined as the production of 1 t of sugar in the biorefinery complex. The calculations were performed for the eight most relevant impact categories including global warming, freshwater eutrophication, terrestrial acidification, terrestrial ecotoxicity, freshwater ecotoxicity, human carcinogenic toxicity, mineral resource scarcity, and fossil resource scarcity. Overall, it was observed that for most of the impact categories, the values were progressively reduced with an increased use of byproducts (i.e., prevention of cane burning and its recovery; filter cake, ash, wastewater, and sludge as fertilizer; bagasse and cane trash for high-pressure cogeneration; ethanol as biofuel and recovery of CO2; biogas for waste to energy production). In general, it could be concluded that an enhanced and efficient use of byproducts would significantly improve the environmental performance of the biorefinery complex.

Normative principles and the sustainable use of geologically scarce mineral resources

The use of geologically scarce mineral resources needs to be reduced substantially in order to prevent future generations from being deprived of them. So far, there has been no international reaction to this growing problem. We argue that an international agreement on the sustainable use of geologically scarce mineral resources is necessary, and in particular that a number of normative principles of environmental governance, as currently codified in international environmental agreements, require such an agreement.

Mineral resources: Geological scarcity, market price trends, and future generations

The extractable ores of the world's geologically scarcest mineral resources (e.g. antimony, molybdenum and zinc) may be exhausted within several decades to a century, if their extraction continues to increase. This paper explores the likelihood that these scarce mineral resources can be conserved in time for future generations without intervening but instead simply relying on the price mechanism of the free market system. First we discuss the role of geological scarcity in the long-term price development of mineral resources. Then, to see whether geological scarcity affects the price of minerals we compare the historical trends in the prices of geologically scarce mineral resources with those of geologically more abundant mineral resources. The results show that in the period 1900–2013 the price mechanism did not result in high prices that provide advance warning of exhaustion of minerals. We therefore argue that if conservation is left to market forces, it is not certain that geologically scarce minerals will be timely, automatically, and sufficiently conserved for future generations. We recommend preparing international policy measures targeted at a price increase of the scarcest mineral resources, in order to accelerate substitution and recycling of these materials and help save the geologically scarcest mineral resources for future generations.

The set-up of an international agreement on the conservation and sustainable use of geologically scarce mineral resources

For more than a century, the use of mineral resources has increased exponentially with annual growth percentages of between 4% and 6%. While for most mineral resources, depletion is not an issue, for some mineral resources the current level of extraction is likely to pose a problem for future generations. Depletion of a mineral resource means that its enriched deposits will have been extracted, and consequently it will become much more expensive for future generations to continue to use these minerals. While technology may reduce some of the adverse effects of depletion, future generations may be deprived of potential innovations for which these specific materials would be essential. The question arises as to how the currently unsustainable extraction of mineral resources can be decreased to safeguard them for future generations. It is submitted that it is unlikely that market forces alone will sufficiently impact the prices of minerals to resolve the unsustainable use of certain minerals timely enough. In this article, it is posited that an international agreement on the conversation and sustainable use of geologically scarce minerals is necessary. The agreement will recognize that the geological scarcity of mineral resources differs between different minerals. It will therefore make a selection of priority minerals, determine how far the extraction rate of these substances must be reduced and decide on a fixed time period within which the extraction must decrease from the current rate to a sustainable rate. The design of such an agreement will be based on two basic principles contained in existing international environmental agreements: (1) the inter-generational equity principle and (2) the principle of conservation of natural resources. Furthermore, the obligatory reduction of the extraction of mineral resources will affect the sovereign rights of resource countries to exploit their own resources. Therefore, any international agreement should make arrangements to ensure resource countries are adequately compensated for their loss of income.

Network Characteristics Analysis of the Xinjiang Regional Logistic Based on Complex Networks

Reasonable logistics system plays a fundamental role in the process of regional economic development. With the development of Xinjiang's energy resources conversion strategy is ceaseless and thorough, as the country imported energy and scarce mineral resources international channel, Xinjiang internal and external logistics hub action are highlighted with each passing day. In this paper the complex network theory is applied to the Xinjiang regional logistics network, important cities, ports, warehousing point for a node to connect these nodes highway straight-line distance of the railway side, constructed the Xinjiang regional characteristics of the logistics network model. Select the node degree distribution, betweenness, average path length, clustering coefficient as a measure, static statistical properties of the network are analyzed. Provide basic data for the Xinjiang regional logistics network.

Silica sand resources in the Netherlands

AbstractSilica sand, (almost) pure quartz sand, is a valuable and scarce mineral resource within the shallow Dutch subsurface. High-grade deposits are exploited in the southeasternmost part of the country, as raw material for the glass, ceramic, chemical and other process industries. Dutch land-use policy requires that scarce mineral resources (including silica sand) are taken into consideration in spatial planning and when preparing for largescale engineering or construction works. For this purpose, and in order to review the long-term possibilities for home production of silica sand, we determined resource potential nationally.Our approach was (1) to establish the relevant conditions and processes associated with the deposition of the currently exploited sands, (2) identify lithostratigraphic units that are genetically similar or are otherwise known to contain quartz-rich sands, and (3) query the Dutch geological survey's borehole database for potential silica sand occurrences within those units. As we have to rely on non-dedicated data, the latter step was undertaken using a largely qualitative set of lithological search parameters. Finally, a limited number of available chemical analyses was used for preliminary verification purposes.Using this approach, we identified three prospective areas: one in the north of the province of Limburg and east of the province of Noord-Brabant(~750 km2), one in the central south of Noord-Brabant (~45 km2), and one in the east of the Gelderland and Overijssel provinces (~1,200 km2). For each area, first-order characteristics of possible silica sand resources are presented (type of deposit, depth, approximate thickness). In the terms of current reporting conventions, we resolved silica sand occurrence to the level of ‘reconnaissance mineral resource’ or ‘exploration result’, and our results do not constitute a formal resource declaration. Available chemical data suggest that the resources in the first two areas could be or become economic, although the grades are lower than those of the currently exploited resources. The third area is less promising in that respect, but available data is too limited to reject the area in this stage. Even so, we tentatively conclude that home production of silica sand can probably be maintained after the reserves in Limburg are depleted.