Dump slope stability is an important activity in the life of an opencast mine. This is because of the safety to mine, machine and personnel as well as economic impact on production. In this paper, stability of heightening of an existing dump is analyzed using analytical method. The waste dump material properties are determined in the laboratory like the cohesion, angle of internal friction, permeability, bulk density, grain density, particle size distribution and in-situ moisture content. The stability of the dump slope is simulated for two extreme conditions of very dry and a wet environmental conditions. Analysis shows that the effects of water on dump stability is more prominent than its bulk density. In these situations, it is pertinent to use the slope stability measures or change the dump profile for better dump stability. In this paper, methodology is developed to ascertain the stability of the existing dump as well as stability analysis by heightening over the older dumps.
Keywords: Waste dump, slope stability, analytical solution
Blasthole drilling process used in opencast mines is one of the conventional methods to extract the ores from ground. During the drilling process, torque available at the bit causes various types of stresses which results in the formation of hole. Tricone bit is one of the most exclusively used bits for the blasthole drilling operation. The drill bit crushes the rock material under its teeth or edges and enables advancement of the drill hole in the intended direction. The bit undergoes very heavy wear and tear which reduces its life, leading to drastic drop in its penetration rate. In this article, the effect of major parameterson the performance of the rotary blasthole drilling as well as on the service life of the said drill bit is highlighted. In this regard, the optimum solutions to increase the service life of the tricone bit and the performance of the blasthole drilling are predicted. This paper also discusses the dynamic behaviors of the blastholedrill rig while drilling in mines.
Keywords: Blasthole drilling; opencast mines; blasthole drill rig; tricone bit
A resource estimate (calculation of total tonnes and grade within a deposit) is generally underpinned by a clear understanding of the geometry, orientation and control of mineralization and set of assays with assigned 3D spatial locations. The proper interpretation and handling of outliers in a data set is crucial to estimating a mineral resource that is representative of the deposit. Without a firm understanding of the distribution of metal in a deposit, mine planning, scheduling, process planning and economic analysis will likely be flawed. Three of the most important issues in the mineral resource estimation process are the recognition of outlier values in a data set, the source of the outlier values, and the subsequent handling of these high values. Treatment of outliers in mineral resource estimations is a perplexing problem for which there is no generally accepted solution. Each deposit may have a unique distribution of outlier values which may require multiple methods of treatment to fully understand the issues and their effect on the mineral resource estimate.
Keywords: Exploration; resource estimation; ore; outliers; block model
Based on the theory of hydrodynamics, a mathematical model of nozzle water jet flow field in hydraulic cutting is established. By numerical simulation for FLUENT software, the effects of nozzle convergence angle, nozzle outlet diameter and cylindrical section length on water jet flow impact is obtained and analyzed. At the same time, a mathematical model of the nozzle outlet velocity is deduced by the simulation results. Furthermore choose optimization of nozzle parameters in the field test, which its convergence angle is 13°, convergence segment length is 10 mm, cylindrical section length is 8 mm and nozzle outlet diameter is 2 mm. Application and testing in coal mine show that this nozzle has the best comprehensive effect in hydraulic cutting field test and improve gas extraction efficiency.
Keywords: Hydraulic cutting; water jet flow field; optimization of nozzle parameters; mathematical model; gas extraction
The paper aims at studying the influence of rules of transparent agent infiltration of coal seam on coal seam gas diffusion.With coal particles in Gecun village, Henan Province as research object, it makes use of adsorption and desorption experiments in high pressure and variable temperature for isothermal and desorption experiments that is based on three common transparent agents, fenton reagent, acetic acid and hydrochloric acid, comparing gas of coal particles before and after infiltration. Moreover, the thesis is on the basis of the new diffusion model of dynamic diffusion coefficient and applies MATLAB software to programming procedure for calculating the original diffusion coefficient D0 of the gas desorption experiment and its attenuation coefficient β. The experimental results are as follows: transparent agents can inhibit gas adsorption of coal particles, and the inhibitory effects of these transparent agents grow stronger from acetic acid, hydrochloric acid to fenton reagent; transparent agents can promote gas diffusion of coal particles, and the inhibitory effects of these transparent agents grow stronger from acetic acid, hydrochloric acid to fenton reagent; transparent agents in coal sem can mitigate outburst risks of coal seam gas with acetic acid the best effect.
Keywords: Adsorption, coal particle, desorption, infiltration, transparent agent
As a case study, YSM oilfield has high water cut and high recovery factor. With various approaches, such as dynamic analysis, reservoir architecture study, simulation and well monitoring, the difference of seepage between planes, interlamination and interior layers can be evaluated, as well as the factors both from geological aspects, such as small structural high, updip sand pinch-out and fault sealing, and engineering aspects such as non-perforation, poor well status which impacted the formation and distribution of remaining oil. The research results suggest that the seepage flow difference is a critical geological factor for the formation and distribution of remaining oil. The vertical seepage to the upper inner differences make the remaining oil mainly distributed in the mid-upper sections of positive rhythm sands. And laterally, sand body splicing zone on plane and the marginal area of main sand body, normally the relatively low permeability area, the local micro tectonic highs and fault sealing affect the distribution of remaining oil in the oil spill area. The vertical distribution of remaining oil is affected by sedimentary rhythm, single sand bottom seriously flooded upper residual oil, residual oil in general oil sand top 1-2 meters. The coupling between geological factors, such as the scale and shape of the sand and the permeability difference between inter layers, and drilling factors such as well pattern design leads to uncompleted or inefficient injection and production pattern, which ends in a variety of remaining oil distribution patterns, such as the planar retention area, undeveloped reservoir and reservoirs with high pressure holding back.
Keywords: Braided river deposits, reservoir architecture, remaining oil, distribution disciplinarian, Da Gang oilfield
One of the challenging problems for surface mining operation optimization for metalliferous deposits is choosing the optimum cut-off grade while doing mine production planning, which is a very important component of mine design process. Many researchers have done significant approaches towards it but till date no full proof solution to this problem has been found. An overview on the selection of optimum cut-off grade, as suggested by various researchers has been presented in this paper.
Keywords: Cut-off grade, net present value, optimization, dynamic programming