The Environmental sustainability of mining in Australia: key mega-trends and looming constraints

At first ‘sustainable mining’ could be perceived as a paradox—minerals are widely held to be finite resources with rising consumption causing pressure on known resources. The true sustainability of mineral resources, however, is a much more complex picture and involves exploration, technology, economics, social and environmental issues, and advancing scientific knowledge—predicting future sustainability is therefore not a simple task. This paper presents the results from a landmark study on historical trends in Australian mining, including ore milled, ore grades, open cut versus underground mining, overburden/waste rock and economic resources. When complete data sets are compiled for specific metals, particular issues stand out with respect to sustainability—technological breakthroughs (e.g. flotation, carbon-in-pulp), new discoveries (e.g. uranium or U), price changes (e.g. Au, boom/bust cycles), social issues (e.g. strikes), etc. All of these issues are of prime importance in moving towards a semi-quantitative sustainability model of mineral resources and the mining industry. For the future, critical issues will continue to be declining ore grades (also ore quality and impurities), increased waste rock and associated liabilities, known economic resources, potential breakthrough technologies, and broader environmental constraints (e.g. carbon costs, water). For this latter area, many companies now report annually on sustainability performance—facilitating analysis of environmental sustainability with respect to production performance. By linking these two commonly disparate aspects—mining production and environmental/sustainability data—it becomes possible to better understand environmental sustainability and predict future constraints such as water requirements, greenhouse emissions, energy and reagent inputs, and the like. This paper will therefore present a range of fundamental data and issues which help towards quantifying the resource and environmental sustainability of mining—with critical implications for the mining industry and society as a whole.     

A heuristic approach to stochastic cutoff grade optimization for open pit mining complexes with multiple processing streams

Cutoff grade specifies the available supply of metallic ore from an open pit mine to the multiple processing streams of an open pit mining complex. An optimal cutoff grade strategy maximizes the net present value (NPV) of an open pit mining operation subject to the mining, processing, and marketing/refining capacity constraints. Even though, the quantities of material flowing from the mine to the market are influenced by the expected variation in the available metal content or inherent uncertainty in the supply of ore, the majority of cutoff grade optimization models not only disregard this aspect and may lead to unrealistic cash flows, but also they are limited in application to an open pit mining operation with single processing facility. The model proposed herein determines the optimal cutoff grade policy based on a stochastic framework that accounts for uncertainty in supply of ore to the multiple ore processing streams. An application on a large-scale open pit mining operation develops a unique cutoff grade policy along with a portfolio of mining, processing, and marketing/refining rates. Owing to the geological uncertainty, the approach addresses risk by showing a difference of 14% between the minimum and maximum production rates, cash flows and NPV.     

Critical analysis of the waste management performance of two uranium production units in Brazil--part II: Caetite production center

This paper discusses the environmental waste management of the Heap-Leach Uranium Production Facility of Caetité located in a semi-arid region in Brazil. A comparison is made with the first uranium production site of the country located in Poços de Caldas. It is demonstrated that differences in the operational process along with different environmental conditions can lead to different impacts. In the present case groundwater is the potential most sensitive environmental medium despite the well-established consensus in the literature that radon and aerosol emissions may turn-out to be the most relevant environmental aspects of an installation located at this type of region. Most of the ²²⁶Ra content in the ore remains in the leached ore that is deposited with the waste rock. A lack in appropriate prediction of the hydrological balance has been causing unanticipated emissions of liquid effluents into the environment. Chemical treatment of this effluent may be needed. Contamination of groundwater in the short term by the waste ponds is not to be expected but it can be a relevant issue in the long term. As a consequence, careful closure schemes will need to be put in place. Finally, the overall costs with remediation in the Caetité production center are lower than those observed at the Poços de Caldas mining site.     

Chinese resource security policies and the restructuring of the Asia-Pacific iron ore market

This paper reviews the restructuring of the Asia-Pacific iron ore market in the wake of the rise of the Chinese steel industry. Prior to the 2000s, this market was characterised by two key features—high firm-level concentration on both the producer and consumer sides, and price determination through annually negotiated benchmark pricing between Australian mining and Japanese steel firms. However, owing to rapid growth in the Chinese steel industry and its emergence as the region's principal iron ore consumer, the Asia-Pacific iron ore market has been dramatically restructured during the last decade. This process has been accelerated since 2005 by Chinese governmental resource security policies, which have sought to address current record high iron ore prices through the use of foreign investment to sponsor new market entrants and the formation of an import cartel amongst the Chinese steel firms. This paper evaluates how these policies have driven restructuring in the Asia-Pacific iron ore market, through an analysis of the growth of China's steel industry, Chinese resource security policies aimed at lowering iron ore import costs, and their effects upon the regional market's ownership structure and price determination mechanisms. It argues that while Chinese investment and cartelisation policies have catalysed significant changes to the ownership and pricing structures of the Asia-Pacific iron ore market, they have carried only mixed benefits for the Chinese steel industry's resource security.     

Global trends in gold mining: Towards quantifying environmental and resource sustainability

In recent years, due to public concern over perceived and actual environmental impacts, the global mining industry has been moving towards a more sustainable framework. For gold mining, there are a number of fundamental issues with regard to assessing sustainability. Commonly perceived as a finite and non-renewable resource, long-term gold production trends include declining ore grades and increasing solid wastes (tailings, waste rock) and open cut mining. Conversely, core sustainability issues include water, energy and chemical consumption and pollutant emissions—also known as ‘resource intensity’. It is important to recognise the links between gold production trends and resource intensity, as this is critical for understanding future sustainability challenges. This paper links data sets on historic gold mining production trends with emerging sustainability reporting to estimate resource intensity, demonstrating the sensitivity of ore grade for gold production and sustainability. Final judgement of the sustainability of gold mining must take account of the sensitivity of the ore grade in the resource intensity of gold production. This has implications for environmental policy and sustainability reporting in the gold mining sector.     

绿色修井作业的环保控制

文章主要阐述了修井作业过程中产生污染物的原因和污染机理,介绍了6种井下作业施工中清洁生产工艺技术,提出了废物资源化利用方式,并针对稠油井常规维护或大修施工前、中、后三期进行分级控制,逐步实现了清洁生产。     

Optimal production scale of open pit mining operations with uncertain metal supply and long-term stockpiles

An open pit mining operation consists of various stages, and the calculation of the production capacities of these stages depends upon the available supply of ore (mineralized material of economic value) and waste material. Cutoff grade is the criterion that specifies the amount of ore and waste. The material with grade equal to or higher than the cutoff grade is classified as ore. The material with grade less than the cutoff grade is considered waste. While this explains the link between cutoff grade theory and the calculation of production capacities, the majority of optimization models for finding production capacities not only disregards this relationship but also ignores expected variations and uncertainty in metal content or the available supply of ore and waste material.     

金尾矿综合利用技术研究与应用进展

黄金矿石的品位低,经选冶后会产生比其他金属矿石更多的尾矿。黄金矿山尾矿的大量排放,造成了黄金和其他有价金属的流失,同时大量尾矿堆积,对环境带来了极大的危害。为进一步回收有价金属,保护矿区的生态环境,重点介绍了尾矿中有价元素的综合回收技术,进一步变废为宝,开发宝贵的二次资源。     

Incorporating environmental issues into optimum cut-off grades modeling at porphyry copper deposits

Cut-off grade is defined as the grade which discriminates between ore and waste within a given orebody. Determination of a complete optimum cut-off grade policy is a very important function during mine life. Using the modified optimum cut-off grade model presented in this paper not only the net present value of a porphyry copper mining project is maximized, but also the adverse environmental impacts of the project are minimized simultaneously. This methodology is more effective in long-range planning. For showing the effectiveness of the model, two scenarios are considered in a hypothetical deposit and the results show that incorporating the modified optimum cut-off grade policy, the net present value will be increased by 3.6% in comparison with the Base Case.     

Mine size optimization using marginal analysis

In this study, a model to estimate the optimum mine size is developed. The model is developed on the basis of marginal analysis. The model solves for the production rate at which the present value of marginal costs equals the present value of marginal revenues—the rate that microeconomic theory shows will maximize the net present value of production from the mine.In addition, the article discusses the effects on the optimum production rate of: the physical characteristics of the deposit, economic factors, and financial factors. It has been found that, not surprisingly, as the reserve tonnage increases, the optimum mine size increases. Also, the optimum production rate increases as the ore grade increases. A direct relationship has been found between the mineral price and the optimum production rate. The optimum mine size is found to be inversely related to the expected growth rate of mineral price, while it is directly related to the expected growth rate of mining costs. A concave relationship has been found between the cost of capital and the optimum mine size.     

Drainage and utilization of Chinese coal mine methane with a coal–methane co-exploitation model: Analysis and projections

Coal mine methane (CMM) released during coal mining attributes to unsafe working conditions and environmental impact. China, the largest coal producer in the world, is facing problems associated with CMM such as fatal gas accidents and intense greenhouse gas emission along the path to deep mining. Complicated geological conditions featured with low permeability, high gas pressure and gas content of Chinese coal seams have been hindering the coal extraction. To solve these problems, a model of coal–methane co-exploitation is proposed. This model realizes the extraction of two resources with safety ensured and has been successfully applied in Huainan coalfield, China. The current situation of drainage and utilization of CMM in China are diagnosed. Connections between the coal production, methane emissions, drainage and utilization are analyzed. Estimations of future coal production, methane emissions, drainage and utilization are made in a co-exploitation based scenario. The emitted, drained and utilized CMM are projected to reach 26.6, 13.3 and 9.3 billion m³, respectively by adapting the assumption of 3800 million metric tons of coal production by 2020.     

Corporate social responsibility in the mining industry: Perspectives from stakeholder groups in Argentina

Since the liberalisation of its investment regime in the 1990s, Argentina has seen a rise in foreign direct investment into large-scale exploration and exploitation of mineral resources. However, many social groups (local communities, grassroots movement and the church) often strongly oppose new mining projects on the grounds of environmental, ethical and economic concerns. In a situation marked by widespread conflict, mining companies continue operating and develop Corporate Social Responsibility (CSR) initiatives which are often promoted as a means of contributing to the sustainability and development of the nation. The paper develops a framework to highlight how the principles of stakeholder theory could be used as conceptual and practical guidance for conflict-resolution oriented CSR policies. The framework is further used to analyse two case studies of conflictive mining projects in Argentina. The paper explores how key stakeholders perceive contribution of CSR to welfare and the socio-economic development of mining communities and sustainable development of the nation. It demonstrates that institutional and social stakeholder networks often strongly oppose the idea of voluntary self-regulation implied by CSR in situations characterised by weak governance. Even though the CSR of companies could be improved in areas of corporate communication, transparency, stakeholder engagement and dialogue, it is not seen as a panacea for the social conflicts in the sector.     

Could a public ecology approach help resolve the mountaintop mining controversy?

In recent years, controversy has grown around decisions related to mountaintop removal mining of coal in Central Appalachia, USA. While this mining method can be particularly efficient, it necessitates removal and relocation of huge volumes of earth—permanently altering the natural landform and potentially impacting local environments and communities. Current decision-making systems and regulatory frameworks have been largely ineffective at incorporating the values and concerns of stakeholders. This is due, in part, to contradicting policies, a legacy of distrust, and problems related to scale. Further, the lack of good civic science related to mountaintop mining and meaningful routes for public involvement have also hampered effective decision-making. We propose that the fundamental concepts of public ecology may provide a progressive approach to resolving these complex issues, and examine the challenges that must be met along the way.     

资源研究面向社会主义市场经济问题刍议

资源研究工作如何面向社会主义市场经济是资源科研机构深化改革中必须解决的重要问题。本文着重从社会主义市场经济对资源配置的要求,自然资源的价格改革和管理,资源的综合利用和节能降耗等方面进行分析,提出了资源研究为社会主义市场经济服务的四条途径。即保证继续进行必要的基础性研究和软科学研究,加强自然资源的非传统性开发研究,资源综合利用与环境保护研究以及资源经济学的研究。     

Some observations on copper yields and ore grades

The paper examines trends in the average copper content of mined ores over the years. It has tended to decline over the long term, but by no means evenly. US averages are not typical of global averages, at least in the past four decades. Those have been both higher, and less volatile than in the US. One reason for falling averages is a change in the type of deposit mined, with a rise in the share of relatively low grade porphyry deposits. The different nature of their deposits is reflected in marked differences in grades between the different continents. African and Australian average grades are higher than the global average, and changes in the share of Central Africa in global output have affected the global average grade. Yields are have been consistently lower in North America than elsewhere, and Latin American average grades have trended downwards, reflecting both the ageing of mines and the rising share of production from porphyry deposits. Typically the yield of mines declines over time as mining proceeds. The average copper content of ore deposits is usually below the average yield of the ore accessed in the early years of production. The initial grades of new mines have not declined over the past forty years, and there has been no perceptible tendency for the average grade of porphyry deposits brought into production to decline over time. There is no apparent correlation between average grade and deposit size, but mine operators tend to exploit economies of scale to offset low grades. The relationship between the annual percentage yields (the head grade) and the reserve grades of deposits is not static. In recent years head grades have fallen closer to reserve grades. The relationship may be affected by movements in metal prices. Although the evidence about the influence of prices is not clear-cut, it does suggest that prices and cut-off grades may be inversely related. As many ores contain other valuable metals besides copper, copper yields will sometimes be subordinated to the extraction of these other metals. Copper equivalent grades have not moved in the same way as copper grades alone.     

New mercantilism: A perspective on how politics is shaping world metal supply

The major countries consuming metals tended historically to be also the major countries producing them. It was in their interest to promote mine development to provide low cost raw materials. Over the past fifty years, the share of global production accounted for by consuming countries has declined and producers and consumers of metals have been slowly moving into separate camps having distinct and differing interests. As a consequence of this, governments of producing countries have become more focused on how to maximise the benefit of metal extraction to their economies rather than on how to supply cheap raw materials; a tendency which has found expression in resource nationalism. Governments of consuming countries have in response become increasingly concerned about the implications of this tendency to their economic development and some countries, most notably China, have adopted robust policies to secure their supplies. Through their actions to influence capital flows within the mining industry and to force metals trade into channels which better serve their national interests (a process characterised here as ‘new mercantilism’), metal producing and metal consuming countries are reshaping global supply.     

Seaborne iron ore trade in the 1990s

This paper discusses how world steel production and seaborne iron ore trade have grown since 1950. The role of steel production forecasts in determining investment in the iron ore industry is examined. Forecasts for world steel production and the demand and supply of seaborne iron ore in the 1990s are presented. It is predicted that world steel production will increase by 64 million tons between 1991 and 2000. This increase will be located principally in the developing countries and China. The corresponding increase in seaborne iron ore trade will be approximately 55 million tons. Expansion projects will be located mainly in Australia and Brazil, but no greenfield iron ore projects will be undertaken. By the end of the decade, the demand for seaborne iron ore will be equal to its supply.     

Recycling utilization patterns of coal mining waste in China

With the fast development of Chinese economy in recent years, China has become the largest coal production and consumption country in the world. Correspondingly, it has produced large quantities of mining waste including coal gangue, coal sludge, fly-ash, coal mine drainage and coal-bed methane (CBM) that are hazardous to the soil, air, and water. Based on the theory and practice of sustainable development and recycling economy, the paper will discuss and analyze the mining waste management in Jincheng Anthracite Mining Group, Shanxi Province, where they have found the paths to realize the mining waste reusing and recycling in colliery. They had established many green industrial chains in the mining waste treatment: the gangue piles turned into man-made eco-park, gangue used for power generation, fly-ash used in the building material, the coal mining water reused and recycled in closed pipelines, the CBM extracted for home-burning and electricity generation, etc. The coal mining waste has been converted into wealth and played more and more important roles in many fields. The practice indicated that these patterns can be applied in other coal mines.     

论对危险废物及副产品的界定和管理

通过厘清固体废物、危险废物、副产物等的概念,分析上述物质及副产品的特性,阐述危险废物和副产品间的转换关系,从适用标准、企业实例两方面入手分析危险废物和副产品该如何界定,着重分析副产品在生产管理过程中的关注点,以期为生产企业及行政管理部门的固废管理工作提供参考.     

低碳经济背景下云南矿业可持续发展对策研究

低碳经济是以＂低能耗、低污染、低排放＂为主要特征的一种经济发展模式。对矿业而论,低碳型矿业是今后发展的必然趋势,但目前云南矿业是＂高消耗、高排放、低利用＂的粗放型发展模式。基于云南矿业的特点及制约因素的分析,提出其可持续发展对策,包括寻求最优开采率、发展矿产资源的深加工、进行企业结构调整、增加集约程度和矿产资源多元化利用、促进废物资源化等。其中,特别要关注尾矿的资源化利用、矿山生态环境的植物修复和煤炭资源的清洁生产。