Fundamental behaviours of production traffic in underground mine haulage ramps

Ramps(or declines) are often used in underground mines to transport ore, waste, materials, and personnel. This paper studies mine ramp productivity and presents results from a set of computer simulations designed to model the fundamental behaviours of ramp haulage systems. Simulations show that, under fundamental assumptions without random disturbances, the haulage system always converges to a periodic behaviour in the steady state, but that productivities vary between equilibria. Simulations also demonstrate how productivity per vehicle does not necessarily decrease as more vehicles are added and,for example, in the five-vehicle case, how a 3.1% improvement can be achieved over the use of four vehicles. The result reveals the inefficiency of commonly-used lockout-style vehicle coordination strategies,and suggests a possible avenue for improving the productivity of haulage ramps by controlling the system to achieve more productive behaviours.

Synthesis, characterization, and property test of crystalline polyferric sulfate adsorbent used in treatment of contaminated water with a high As(Ⅲ) content

A crystalline polyferric sulfate(PFS) adsorbent was synthesized by oxidizing and precipitating ferrous ions in air atmospheric conditions. The morphology, structure, specific surface area(SSA), and adsorptive efficacy of the adsorbent to As(Ⅲ) were characterized by scanning electron microscope(SEM) and transmission electron microscopy(TEM) images, X-ray diffraction(XRD) patterns, Fourier-transform infrared(FTIR) spectra, BET SSA analyses, and adsorption experiments. The adsorbent showed a near-spherical aggregate structure and had good crystallinity. A significant amount of α-goethite co-precipitated with PFS in the case of the initial ferrous concentration of 1 mol/L and increased SSA of the adsorbent. The stability region of ferric compounds in the process was drawn and applied to analyze the iron behavior during the synthesis. The adsorption of As(Ⅲ) in high As(Ⅲ)-containing solutions fitted the Langmuir isotherm model adequately. The absorbent with co-precipitation of α-goethite showed good adsorbability for As(Ⅲ) and good filtering performance in the high As(Ⅲ)-containing solution of 10–100 mg/L under acidic, neutral, and alkaline conditions(pH 2.09–9.01). After the adsorption process, the stability of the residues bearing As(Ⅲ) was evaluated by toxic characteristic leaching procedure(TCLP) tests. The results indicated that the residues were extremely stable, and the concentrations of arsenic in the leaching solutions were less than 0.01 mg/L.

A study of self-heating characteristics of a pyrrhotite-rich sulphide ore stockpile

Original surface chemistry of sulphidesis altered upon contact with air, leading to ''oxidation'', which is accompanied by evolution of heat. The current study reports results of an investigation on extent of exothermicity of an experimental nickel-copper sulphide stockpile that was formed at a mining site in Sudbury, Canada. The ore contained pentlandite and chalcopyrite that are accompanied by a large quantity of pyrrhotite. The self-heating characteristics were recorded by temperature sensors placed inside the stockpile. Ambient conditions such as temperature, humidity, and wind velocity were simultaneously recorded. The inner temperature of the stockpile indicated significant fluctuations due to rapid changes, particularly in the outside temperature. The minimum and maximum temperatures recorded in the outside and inside were 5 and 10.5, 44.3 and 32 ℃, respectively. The self-heating capacity of the sulphide ore stockpile observed represents a mild case compared to that experienced by coals. Possible reasons are discussed.

Thermodynamics of the Reduction Roasting of Nickeliferous Laterite Ores

The global nickel sulphide resources are becoming more difficult to mine and, as a result, there is increasing interest in the current and future development of the oxidic nickel laterite deposits. In comparison to the sulphide ores, the nickel laterites cannot be readily upgraded by conventional means and growing attention is being focused on the development of new methods for processing these ores. In this paper, firstly, brief overviews of laterite ore mineralogy and the conventional techniques used to extract the nickel from both the limonitic and the saprolitic nickeliferous laterites are provided. Secondly, previous research on the thermodynamic modelling of the reduction of the laterites is discussed. Thirdly, an improved thermodynamic model is used to predict the equilibrium products arising from the solid state reduction of both the limonitic and the saprolitic ores. Based on these thermodynamic predictions, the reduction behaviors of the two ore types are compared in terms of nickel recovery and grade in the ferronickel product. The effects of reduction temperature, ore composition and carbon additions were studied. Finally, the results from the simulations are compared to the experimental data available in the literature.

On the design and selection of vehicle coordination policies for underground mine production ramps

Traffic management in underground mines,especially on production ramps,is a difficult problem to optimize and control.Most operations use one of a few common policies;e.g.,the so-called ‘‘lock-out" and‘‘loaded-vehicle-priority" policies.The work presented in this paper uses discrete-event simulation to study the efficiency of multiple policies.Based on simulation results,an improvement to the common lock-out policy is proposed.This new policy utilizes the rules of the lock-out policy but integrates an option that allows a group of vehicles to be given temporary priority in a certain direction of travel.Quantitative results are provided and,based on these,a systematic technique for ramp design that aims to optimize the efficiency of underground mine ramp traffic flow is described.

废三元锂离子电池正极材料脱锂渣的淀粉还原浸出动力学

以淀粉为还原剂从废三元锂离子电池(LIBs)正极材料脱锂渣中回收Ni、Co和Mn,并研究其浸出动力学和机理。系统地研究搅拌速率、浸出温度、H_(2)SO_(4)浓度和淀粉用量对Ni、Co和Mn浸出率的影响。结果表明,在搅拌速率为500 r/min、硫酸浓度为1.5 mol/L、淀粉用量为6 g/L、浸出温度为80℃和浸出时间为60 min的优化条件下,Ni、Co和Mn的浸出率分别达到98.07%、96.52%和98.06%。根据冶金过程液固反应动力学模型,脱锂渣的浸出动力学可以用化学反应控制的未反应收缩核模型很好地进行描述。在浸出反应中,Ni、Co和Mn的表观反应活化能分别为93.32、102.84和95.68 k J/mol,H_(2)SO_(4)的表观反应级数分别为0.9225、1.0335和1.1285。淀粉容易制取、成本低,可取代传统还原剂用于从废三元锂电池中提取有价金属。

Estimating underground mine ventilation friction factors from low density 3D data acquired by a moving LiDAR

Ventilation system analysis for underground mines has remained mostly unchanged since the Atkinson method was made popular by Mc Elroy in 1935. Data available to ventilation technicians and engineers is typically limited to the quantity of air moving through any given heading. Because computer-aided modelling, simulation, and ventilation system design tools have improved, it is now important to ensure that developed models have the most accurate information possible. This paper presents a new technique for estimating underground drift friction factors that works by processing 3 D point cloud data obtained by using a mobile Li DAR. Presented are field results that compare the proposed approach with previously published algorithms, as well as with manually acquired measurements.

深部矿井的地应力场

地应力是任何地质力学设计任务的重要组成部分。在深部矿井中,这个要求更是重要。深矿中地应力不仅导致挖掘边界断裂,而且会诱发地震活动和应变爆裂、岩爆等相关问题。在矿井中测量地应力的传统方法是使用应力解除法拟合主应力,还可以使用区域应力数据汇编。两种方法都假设应力场相对简单,拟合过程中都对数据进行平滑以减少数据离散性。类似的方法通常应用于模拟断层和其他地质结构,因为它们在初期均匀的应力场中产生。在已发现的深矿的典型复杂地质环境中,有证据表明这些方法并不可用。应力场和地质结构之间的相互作用导致应力大小和取向的自然离散。在一些矿井中,这些变化很明显,对于特征设计也很重要。传统的测量和分析方法不能很好地适用于量化或再现这种应力场的行为。诱发地震活动是深部矿井的共同特征,地震数据通常也很丰富。起源于地壳地震分析的地震应力反演方法可以提供关于主应力方向及其相对大小的信息。其在釆矿地震活动中的应用已经很少,但是该方法具有在空间和时间上映射应力场的潜力。有例子表明该方法能够探测到大地震附近局部应力场的重大变化。该方法只能用于诱发地震,因此不能代替传统的应力测量。然而,在开挖的矿井中,它可以为矿井规划提供有价值的信息,并且可以更好地理解深层矿井中典型复杂地质环境中的断层与应力场之间的关系。

Environmental sustainability opportunity and socio-economic cost analyses of phosphorus recovery from sewage sludge

Although phosphorus(P)recovery and management from sewage sludge are practiced in North America and Europe,such practices are not yet to be implemented in China.Here,we evaluated the environmental sustainability opportunity and socio-economic costs of recovering P from sewage sludge by replacing the current-day treatments(CT;sludge treatment and landfill)and P chemical fertilizer application(CF)in China using life cycle assessment and life cycle costing methods.Three potential P recovery scenarios(PR1‒PR3:struvite,vivianite,and treated sludge)and corresponding current-day scenarios(CT1‒CT3 and CF)were considered.Results indicated that PR1 and PR2 have smaller environmental impacts than the current-day scenarios,whereas PR3 has larger impacts in most categories.PR3 has the lowest net costs(sum of internal costs and benefits,39.1-54.7 CNY per kg P),whereas PR2 has the lowest external costs(366.8 CNY per kg P).Societal costs for production and land use of 1 kg P by P recovery from sewage sludge(e.g.,∼527 CNY for PR1)are much higher than those of P chemical fertilizers(∼20 CNY for CF).However,considering the costs in the current-day treatments(e.g.,∼524 CNY for CT1),societal costs of P recovery scenarios are close to or slightly lower than those of current-day scenarios.Among the three P recovery scenarios,we found that recovering struvite as P fertilizer has the highest societal feasibility.This study will provide valuable information for improved sewage sludge management and will help promote the sustainable supply of P in China.