Applications of the random model of drainage basin composition

The random model of drainage basin composition is founded on the assumptions that (a) natural channels are topologically random in the absence of geological controls and (b) for channel networks developed in similar environments, the exterior and interior link lengths are independent random variables with a common distribution for each type. The effectiveness of this model in estimating the values of geomorphic variables and in explaining and predicting geomorphic relationships is illustrated by several examples. The data required for these examples were obtained from map studies of 30 channel networks, comprising a total of about 8700 links, in eastern Kentucky. A common factor in the success of all three applications of the model is the way in which the planimetric features of drainage basins are determined by their underlying topologic structure.     

A mass balance approach to estimate the dilution and removal of the pollutants in stream water polluted by acid mine drainage

 A few simple mass balance equations were developed to simultaneously estimate how much the pollutants from acid mine drainage (AMD) in stream water are diluted and removed during their migration. The application of the equations requires knowledge of the variations in the concentrations of the dissolved pollutants and the stoichiometry of the precipitation reaction of the pollutants when none of the pollutant shows a conservative behavior along the stream path. The calculation should be restricted to the pollutants showing much higher concentrations in the polluted main stream water than in the combining or diluting water of the same target area. The mass balance equations were applied to estimate the dilution factor and precipitation fractions of pollutants in Imgok Creek such as Fe, SO₄ and Al from the AMD of Yeongdong mine. The results show that the estimation, especially for SO₄ and Al, significantly depends on the kinds of the precipitates. When FeOHSO₄ and AlOHSO₄ are assumed to precipitate, the maximum removal fractions of SO₄ and Al by precipitation are respectively 34% and 46% of the original input, which is much higher than the values estimated when SO₄ is considered to be perfectly conservative. It indicates that the stoichiometry of precipitation reaction is very important in the interpretation of the pollutant dilution and migration and assessment of environmental impacts of AMD. The applicability of the mass balance equations may still need to be verified. However, examining the calculated dilution factor and precipitation fractions with the equations can provide invaluable information on not only the behavior but also unexpected input of the pollutants in the stream water polluted by AMD and other point sources. Received: 12 November 1997 · Accepted: 30 March 1998     

Role of hypsometry and planform in basin hydrologic response

The effects of variations of drainage basin morphometry and relief characteristics on flood peak magnitude and time-to-peak are investigated using simulated stream networks. The networks are produced by three models: headward growth, systematic capture, and minimum power relaxation. Translational and kinematic wave flood routing were used to generate synthetic hydrographs. Peak discharge and time-to-peak are predictable to a high degree by five different sets of morphometric-relief parameters. In order of decreasing order of importance in predictive ability the parameters characterize basin size, relative relief, basin concavity, and basin shape. Both simulated and natural stream networks exhibit strong dependence of planimetric morphometry upon basin concavity. The effect of this dependency is to increase the effect of basin concavity upon flood hydrographs.     

The geology of Australian Mars analogue sites

Australia has numerous landforms and features, some unique, that provide a useful reference for interpreting the results of spacecraft orbiting Mars and exploring the martian surface. Examples of desert landforms, impact structures, relief inversion, long-term landscape evolution and hydrothermal systems that are relevant to Mars are outlined and the relevant literature reviewed. The Mars analogue value of Australia's acid lakes, hypersaline embayments and mound spring complexes is highlighted along with the Pilbara region, where the oldest convincing evidence of life guides exploration for early life on Mars. The distinctive characteristics of the Arkaroola Mars Analogue Region are also assessed and opportunities for future work in Australia are outlined.     

A dual site study of the rainwater chemistry within the Western Pacific region

The two-year (1999–2000) rainwater chemistry at two monitoring sites in nearby coastal areas [Taiwan (TW) and Hong Kong (HK)] within the Western Pacific region has been studied. The volume weighted average pH values for the entire sampling period in TW and HK were 4.6 and 4.2, respectively. Sea salt Na⁺ and Cl⁻ were the most abundant species in the TW samples but and H⁺ were the most abundant in the HK samples. The sea salt and concentrations at TW were higher than those at HK both in the cold and warm seasons. Chloride depletion was minimal in the rainwater samples at both sites. Non seasalt- was associated with . Under the influence of the East Asian Winter Monsoon, the back-trajectory studies revealed that elevated anthropogenic species concentrations were associated with trajectories (1) very near to the continental boundary layer of Mainland China; or (2) along the coastline of Eastern China where large cities/industrial areas are located or (3) passing through the region of stagnant air over Northern/Eastern China. The lowest anthropogenic and crustal species concentrations measured in HK are associated with the summer monsoon and are attributed not only to the clean marine air masses but also to the relatively low SO₂, NO _x and NH₃ emissions from the South/ South East Asian countries, as well as infrequent biomass burning activities and wet scavenging at sources during the summer months. Approaching tropical cyclones led to the lowest pH values (4.2 in TW and 3.8 in HK) amongst the other weather categories. The findings here have been compared with other studies within East Asia and elsewhere.     

金川二矿区14行风井返修支护效果分析

针对金川二矿区14行风井的返修支护方案,本文根据金川矿区高应力破碎岩体的条件,从锚杆、喷射混凝土、钢筋网三方面,分析了该方案中喷锚网支护的作用机理,并通过数值方法分析了该返修支护方案的效果。研究结果表明:14行风井的返修支护措施对竖井围岩移动、变形有一定的限制作用,但效果不是很好;随着开采深度和规模的扩大,井筒围岩还将产生较大的位移,并有可能重新发生破坏。     

云南矿山深部找矿新突破及启示

会泽超大型富锗铅锌矿、澜沧老厂大—超大型银铅多金属矿床和保山金厂河航磁异常深部找矿,先后取得重大突破,推动云南新一轮新、老矿山和磁异常区深部找矿积极性。建议禄丰中兴井125#—元谋甘泉村航磁异常、巧家药山航磁异常与石屏龙潭含多金属铁帽等的深部找矿应及早提上议事日程。     

矿山地质环境治理工程预算探讨

经过最近几十年大规模矿业开发,我国矿山地质环境问题比较突出。国家投入的治理资金也愈来愈多,但预算过粗、不细化、不合理支付、使用效率低等现象愈来愈严重。本文以阜新海州露天矿矿山治理工程投资预算作为案例分析,通过预算取费标准、预算说明、治理工程量及工程单价预算等几个方面,进行了投资估算分析,对矿山企业申请国家治理资金、编制矿山地质环境保护与治理恢复技术方案预算,具有借鉴意义。     

辽宁省红透山铜锌矿床地质特征及外围找矿潜力分析

近几年由于国家深部找矿项目的实施,红透山矿床深部（距地表1500米以下）发现厚大矿体,新增资源量可延长矿山寿命仅50年。这一深部找矿重大成果的取得,进一步促进了对该类型铜锌矿区域找矿的研究。本文通过对该矿地质特征、矿床成因、成矿规律、地质化探成果的进一步研究,分析认为区域上该类型矿床尚有巨大找矿潜力,并指出了下步找矿主要方向,旨在通过深部找矿成果的取得,促进外围找矿的突破。     

辐射井疏干技术在露天矿地下水疏干中的应用研究

现有的井群疏干、地下巷道集中排水、地表地下联合疏干方法都已比较成熟有效,但当矿区的地下水系统由非均质各向异性、低渗透性含水介质组成时,井群疏干受到低渗透性含水层和高倾角裂隙的制约,无法达到良好的疏干效果。地下巷道集中排水方法一次性工程投入很大,含水层富水性极度不均时易造成许多不必要的浪费;地表地下联合疏干方法的地面部分对矿坑边坡安全和采场作业都会造成一定的影响。结合马钢集团南山矿业公司高村露天铁矿的地下水疏干技术研究专项,调查分析了矿区地质和水文地质条件,含水介质特点及含水层富水特征,借助GMS软件建立了高村矿区地下水水流模型,提出了辐射井疏干技术的设想,并依据前人提出的＂渗流-管流耦合模型＂模拟辐射井,完成了此类矿山的地下水辐射井疏干方法的初步研究。