查看更多>>摘要：Many of Britain's reclaimed coal-lands aredamaged by erosion. Much accelerated runoff and erosion iscaused by soil compaction that reduces the land's capacity ofabsorb rainwater. This study compares conditions in tow types ofcoal-spoil, deep-mine colliery discard and surface-coal-mineoverburden, and in four contexts: freshly laid spoil, oldunvegetated minespoil, minespoil partly veneered by grass tufts,and 'reclaimed' spoils, which are defended by a dense grass turfand (ca. 100 mm) deep artificial topsoil. Bulk density testingreveals a characteristic pattern. The soil is of moderate density (<1.3 g/cm~3) in the grass root zone. However, soil densities riseto 1.8g/cm~3 and more between 30 and 50-cm depth Particle sizeand stability tests confirm that minespoils contain a largeproportion of water unstable primary particles, mainly mudstonesand shales. These break down on wetting, flood the soil with fineparticles, and help raise the soil density to levels where waterinfiltration and root penetration is impeded. Rainfall simulationtests on surface coalmine spoils near Blaenavon, Wales, find thatpoorly vegetated plots (50-90 percent cover) convert less rainfallto runoff and yield a fourth as much sediment as unvegetatedplots. Tests of deep coalmine spoils at the Earth CentreReclamation Project, Doncaster, England, found that newly laid,unvegetated, recently washed and hence stabilised, coal spoilsconverted only 20 percent of rainfall to runoff. Older compacted,spoils converted 25-35 percent of the rainfall to runoff whenunvegetated but less than 10 percent A when mantled by thingrass turf Soil losses for the same rain event were more than fourtimes greater on the unvegetated sites. Finally, on both sites, plotsmantled with a deep well-managed layer of applied topsoil sitesabsorbed most of the rainwater applied in tests. This wassubsequently detected running in macropores and fissures belowthe applied topsoil and in the upper layers of the relativelyimpermeable mine-spoil subsoil.
查看更多>>摘要：The comminution function is just one in a longchain of value-adding functions that begins with ore in theground and ends with the dale of metal, concentrate or someother product. The creation of an economic model forcomminution is complicated by the fact that it is difficult toidentify the exact amount of value added by comminution, andfurther complicated by the fact that changes in comminution on arange of other associated functions such as ore-wastediscrimination (cut-offs), mine scheduling and down-stream processing.The authors argue that in order for comminution to be modelledeffectively, it must be incorporated into a framework whichincludes many other related functions. In this way, a change in thecomminution circuit can be evaluated after taking into accountits effect on other related activities.This paper also presents a significant innovation which allows thesimultaneous optimization of milling time and processing cut-offs, with the objective of maximising NPV.
查看更多>>摘要：Several former coke works sites in north-eastEngland are under consideration for redevelopment forresidential or commercial use. In some instances thecontamination from the coking processes has spread off-sitethrough groundwater and investigations have been undertaken toascertain the extent of contamination. This paper focuses on onevery large site covering 91 hectares, Hawthorn Colliery, wherecontamination may have spread onto the so-called HawthornReserve Site through groundwater movement Details ofinvestigations and proposed remedial measures are provided. AtHawthorn the services of an industrial archaeologist wereengaged to research details of the actual operations at the collierysince their commencement in 1957. This enabled the siteinvestigation to be focused on areas of highest contaminationpotential. A phased approach to the investigation was carried outand at the end of each phase both the geological andcontamination aspects were assessed and examined thoroughly inorder to economically plan each subsequent phase. Theinvestigation concentrated on locating the thickness and extent ofsand and gravel layers within the glacial till and determining thepermeability of these layers, as these layers provide a potentialconduit for contaminants from the former colliery site to theadjacent Reserve Site.
查看更多>>摘要：Cable sensor which is usually used for invaderinspection of sensitive places such as atomic power stations andother high security is considered to be available for rock noiseand impact detection, because the sensor can detect vibration atany point of a string, and can be used with extending more than ahundred meter or more. From a field test using cable sensor andmobile multimedia network, it was found that the impact sourcecaused by a steel ball dropping in the proximity of the sensingcable could be judged clearly from the order of rise time ofsignals of cable sensors, amplitudes of wave forms of signals anda topography pictured from peak values of signals transmitted byway of mobile mulumedia network. This newly developed systemis considered to be applicable not only to detect the resultantimpact of fallen rocks but also to monitor the noise produced bythe fracture of unstable rocks and sounds of falling rocks along a slope.
查看更多>>摘要：Airborne respirable dust surveys were conducted atsix surface coal mines to investigate the effectiveness of dustcontrol methods used on rotary rock drills and bulldozers. Dustcontrols commonly used on drills include a dry dust collectionsystem, exhausting from a shrouded area around the collared hole,and an enclosed drill operator cab, filtering airborne dust fromthe cab. Bulldozers arc also typically equipped with an enclosedoperator cab as a dust control measure. Airborne respirable dustsampling was conducted near each equipment's source ofgeneration and inside its enclosed cab. Silica analysis wasperformed on the dust samples to determine the percent silicacontent in the dust generated at the six mining operations. Anadditional eight-month follow-up of dust sampling was alsoconducted in the enclosed operator cabs of several rock drills andbulldozers. Data were analyzed for long-term variability ofaccepted control methods to abate dust and silica levels.The highwall rock drill was the major and most variable dustsource as compared to the bulldozer, generating dust levels, onaverage, one order of magnitude higher than dust levels of thebulldozer. Four of the six drills surveyed had dust containmentand capture problems at the shrouded drill table above the hole.Repairs or modifications to three of the drill dust collectionsystems were shown to reduce dust levels by more that 50 percentnext to the shrouded drill table. The enclosed operator cabsprovided more than 90 percent and more than 40 percent lowerdust levels than at the dust source for the drill and bulldozer,respectively. Long-term sampling of several of these highwalldrills and bulldozers showed that the dust levels in the drill cabswere frequently higher than 0.2 mglm~3 and more variable thanin the bulldozers. The bulldozer dust levels were frequentlybelow 0.2 mg/m~3. Future research should focus on improvingsome of the deficiencies present in the drill's primary dustcollection system, and developing quality control methods toensure the integrity of enclosed cab protection for equipment operators.
查看更多>>摘要：A variety of algorithms are available for short-termmine production scheduling. All assume that the keycharacteristics of the deposit model are smooth and that a uniquerepresentation of the orebody exists. Is the current approach toproduction scheduling valid if these assumptions are violated?Both a stochastic orebody model based on conditional simulationand an estimated model based on kriging are used as input to amath programming-based scheduler. Deviations in resultingschedules are presented in terms of the impact of geologicuncertainty on production, the efficacy of the traditional approachand suggestions for integrating stochastic models into theproduction scheduling framework.
查看更多>>摘要：The use of computer modelling has long been asubject of interest and numerous models have been developed ofmining and geotechnical applications. Over the years theGeotechnics Group of School of Chemical, Environmental andMining Engineering (SChEME) al the University of Nottinghamhas been engaged in a number of applied research activities,including surface subsidence, strata caving behaviour, Rock MassClassification and roadway support design. With the increasingclosure of mine workings, the Group is actively investigating theenvironmental problems associated with active and abandonedmines. The paper briefly introduces some of the on-goingresearch projects in mining related problems using computer-modelling techniques.
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