外文翻译了解矿区水和盐的动态 支持集成水质和质量管理.docx

1、外文翻译了解矿区水和盐的动态 支持集成水质和质量管理中文3600字本科毕业设计（论文）外 文 翻 译原文：Understanding mine site water and salt dynamics to support integrated water quality and quantity managementWater reuse is becoming an integral component of the water management strategy on mine sites. This practise is being driven by corporate sus

2、tainability goals, community and societal pressures to demonstrate improved water stewardship, as well as climate and regulatory pressures. However, water reuse often results in water quality compromise which can then result in decreased recovery through problems in processing circuits, product qual

3、ity, and an increased likelihood of discharge of water that cannot meet environmental regulatory requirements. On most mine sites, there is usually a disjuncture between water quantity management and water quality management with the latter being managed solely as an environmental problem. It is bec

4、oming increasingly clear that water quality and quantity must be managed as an integrated system. In order to integrate water quality and quantity management to achieve multiple objectives the dynamics of water and constituents must be understood. Using examples from a study being conducted at a coa

5、l mine the Bowen Basin, this paper will outline the dynamics of water and salts on the site.IntroductionThe need for sustainable water management practises is being driven by corporate sustainability goals, increased public scrutiny of water use, management, and environmental stewardship, the relati

6、ve economics of increasing reuse against the alternative of increased supply of fresh water and climate conditions. The ability to simultaneously meet water quantity, water quality and product quality objectives is becoming an increasingly challenging component of water management on mine sites. How

7、ever, because the water system on a mine site acts as a complex system with feedbacks and interactions between the natural climate driven system and the engineered reticulation there are often unintended impacts from water management decisions that only consider one set of objectivesIn the coal indu

8、stry, there has been considerable investment in improving water management on sites. This has been driven by widespread and prolonged drought as well as corporate targets for freshwater savings. Over the last decade most sites have adopted water reuse as a means for making freshwater savings. Howeve

9、r, water reuse results in increased salinity in site water stores (Moran et al, 2006). The increase in salinity is driven largely by evaporation and ongoing salt inputs from spoil, coal and groundwater. Effective management of dissolved salts can provide opportunities for reducing risks and costs in

10、 managing water and the environment, processing efficiency, product quality and operating/maintenance.In order to manage both water quality and quantity in an integrated system to meet multiple objectives on coal mines requires an understanding of the nature and sources of salts; the dynamics of the

11、 salt fluxes on a site; and the impact of water quality on production and product quality. These factors must also be balanced against the risk of non-compliant discharge. The aim of this work was to increase understanding of the mine and climate conditions that result in salt fluxes from various pa

12、rts of the site into the mine water reticulation system. With this information, operational guidelines can be developed that allow sites to proactively, rather than reactively manage the water system to meet multiple objectives.This paper will present data that illustrate the responses of representa

13、tive water bodies on the sites to changing climatic conditions. Previous modelling of water and salt fluxes has assumed that salts behave conservatively, ie that salt concentration of a water body will only change in direct proportion to the mixing of input waters with different salt concentrations

14、(eg Moran et al, 2006). While this is a generally acceptable assumption for predicting total salt concentrations and the overall implications of water management strategies, many individual ions comprising the salt load may participate in biogeochemical reactions which may dramatically alter the ion

15、 composition of a water body. This altered ion composition may have impacts on particular processes. For example, it is known that divalent cations (Mg and Ca) provide greater flotation benefits during coal washing than monovalent cations (Ofori et al, 2005). Thus it is important to not only underst

16、and the dynamics of total salts on a site but also the principal processes governing the concentrations of individual ions comprising the salts.One of the difficulties in understanding the dynamics of water and salts on mine sites is that it is difficult to distinguish between water from different s

17、ources and therefore accurately attribute salt fluxes. Inputs from a number of water sources, eg groundwater, run-off, etc cannot be metered. In this work stable isotopes Oxygen- 18 (denoted d18O) and Deuterium (denoted dD) have been used in conjunction with geochemical signatures to trace inputs fr

18、om these unmetered water sources6 Times series of cation (top) and anion (bottom) concentration changes determined in surface waters of PitF. Average (z1 sd). Deep water concentrations are shown for comparison7 Cation (top) and Anion (bottom) composition of run-off from spoil and roadRun-off composi

19、tionAlthough run-off from spoil is not a large input to Pit F due to the small catchment area, the contribution via this process appears to impact the surface water ion composition as discussed below. This process may have a more pronounced impact on the water quality of water stores with larger cat

20、chment areas or areas with highly active spoil. Changes to rainfall composition during runoff from spoil and roads is shown in Figure 7 and total concentrations as a proportion of total ions in Figure 8. Rainfall composition is taken from Brasell and Gilmour (1980) and Probert (1976). Based on the m

21、ethod of collection and similarity between the d18O and Dd composition of the run-off samples and rainfall (Figure 9), the run-off samples collected in this study are likely to mostly reflect composition of surface or fast flow path run-off rather than run-off from rainfall that has infiltrated the

22、spoil before flowing to the pit. Fast flow path run-off may also include infiltration through cracks or fractures in the spoil. Thus the ion composition of these samples may differ significantly from the total run-off (surfacezinfiltration) entering the pit during events due to the shorter contact t

23、ime of the rainwater with spoil. Ongoing work is being conducted to elucidate the relative importance of surface and deeper flow paths through spoil and consequent ion inputs delivered to the pits under different conditions.What is apparent from Figures 7 and 8 is that there is considerable variabil

24、ity in both the amount of salts delivered via run-off and the relative proportion of ions in solution. Comparison of the ratio of Ca, Mg relative to Na and Cl : SO4 between Pit F run-off and rain composition is consistent with the observed changes in surface water composition shown in Figure 6. Vari

25、ability between the spoil run-off samples is likely to reflect spatial variability in the spoil properties across the site. Further, Gozzard 8 Relative proporation of cations (top) and anions (bottom) determined in run-off from spoil and haul roadsetal(this volume) suggested that both salt dissoluti

26、on and cation exchange with clays may be important mechanisms by which the cation composition changes during run-off fro spoil. Comparison of average pit water composition for Pit F and Qs with run-off composition and sequentially extracted salt and exchangeable fractions frmom spoil samples (Figure

27、 10) suggests that the mechanism by which cations are mobilised to solution are also spatially variable. The dynamics of cation composition in Pit Qs and associated run-off, for example, appears to be dominated by salt dissolution. In contrast the cation composition of both run-off and the salt frac

28、tion for Pit F are far more variable (Figure 10b). Comparison of run off and the sequential extraction data with the Pit F composition suggests that while salt dissolution is likely to be an important input mechanism, cation exchange may also play a significant role in determining the composition of

29、 run-off from rehabilitated areas to the pit.Providing consistent water quality for coal washingIn most cases sites can adapt processes to accommodate different water quality. For example, most coal mines in the Bowen Basin have shifted from using freshwater to salty water for coal washing. In this

30、instance switching to salty water provided benefits by improving flotation with reduced reagent use (Ofori et al, 2005). However, in situations where water quality changes on relatively short time scales such as shown in Figure 4, adaptation is not usually possible because in most cases sites do not

31、 have sufficient information or tools to predict changes in water quality. Often it is assumed in the CHPP that changes in ROM coal properties are the source of variation in flotation performance. Properties of the feed coal are monitored whereas water quality parameters are not typically monitored.

32、 Figure 11 shows changes in flotation reagent use during the wet season of 2007/2008. It can be seen that both frother and collector usage was increased as flotation yields decreased due to the lower conductivity of the feed water. During this period while there were some changes in feed coal proper

33、ties, the primary factor affecting flotation was the changes to water quality. During these rainfall events the operators were not aware of the conductivity changes in the feed water and so were responding reactively rather than proactively to maintain production.At German Creek providing relatively consistent water quality for coal washing, even dur