A computer simulation model of a surface blast

Abstract

Accurately planned and executed blasting makes for efficiency and economy. A knowledge of the number of misfires and blasting failures is essential in achieving good blasting. Bench blasting relies on delay firing for maximum fragmentation, a reduction in ground vibration, and proper overbreak. The amount of delay is specified by the manufacturer, but in practice these delay times are average value times, and the actual delay times stochastic.

Using the statistical distribution of the actual delay times, a simulation model is constructed which can be used to determine the most economic and efficient blast plan. Allowances can be made for different types of faces and blasts. The computer program used is described here. The program is quite general and can be used to simulate a vide variety of different blast configurations to study blast failures.

The programming language used is GFSS and the program can run on a personal computer (using GPSS/PC). The program can be modified for different blast configurations in a matter of minutes. Results for a typical blast are given.

It Is shown that the GPSS language provides a simple, open cut face.     

Operational ore/waste classification at a surface gold mine

Abstract

The daily determination of ore blocks and waste blocks in a surface gold mine can be formulated as a binary integer programming problem. While the geometric mining constraints complicate the problem beyond the capabilities of standard algorithms, the special structure of the problem allows the development of a fast alternative. Using the theory of generalized Lagrange multipliers, the problem can be decomposed into a series of one dimensional problems amenable to a dynamic programming solution.     

Damage in rock under explosive loading: Implementation in DYNA2D of a TCK model

Abstract

The rock fragmentation, that allows its mining, is the main objective pursuited in blasting. The purpose of this paper is to review a material model to which a rock under an explosive detonation may respond. A well-known model, TCK, to compute damage, previous to rock fragmentation, has been analysed. A source code to implement the model has been written, and the logical secuence of necessary operations for the computer coding is described in detail.     

Simulation of truck haulage systems in surface mines

ABSTRACT

Computer simulation can be used as a means of experimentation and evaluation of both truck allocation and dispatching problems especially when analytical methods are not suitable. The simulation language known as Q-GERT is introduced and evaluated in terms of its applicability to the modeling of surface mining activities. Through the analysis of a wide variety of situations, the program is proven to be an accurate modeling method.     

Monitoring networks for open pit mines

ABSTRACT

Monitoring networks are used in open pit mines to ensure safety of men and equipment and avoid disruptions in the mining operation. The methodology applied to monitoring networks includes their design, selection of suitable instrumentation, control of systematic errors, and analysis of the observational data. In this paper it is proposed that the methodology suggested in Larocque (1977) be modified to give a more reliable determination of movement. A BASIC computer program suitable for a hand held computer, which enables one to detect statistically significant horizontal movement in the field, is also given.     

Use of genetic algorithms in a mining problem

ABSTRACT

This paper introduces the principles of genetic algorithms and presents their properties and structure. The application of genetic algorithms in the mining problem of ore grade estimation is discussed and the results are compared with previously published data. The outcome of this paper indicates the potential of genetic algorithms in mining applications.     

Generating decision maker preferred production plans

Abstract

Generating a mine plan that is acceptable by the decision maker (eg, mine manager) is a regular problem for the mining analyst (eg, mining engineer). This problem looms larger when the decision maker does not guide the process. This phenomenon is typical of single objective and single criterion-oriented optimisation methodologies which are not designed to involve the decision maker. The process of generating a decision maker's preferred production plan involving multiple objectives and multiple decision parameters is demonstrated here using PARETO OPTIMAL STOCHASTIC SERIAL DYNAMIC PROGRAMMING. The process requires the mining analyst to generate a superior set (pareto set) of alternatives out of the usually numerous set of feasible alternatives. The decision maker then conducts a careful study of the pareto set and declares his level of preferences for the objectives. Finally, the mining analyst generates the production plan preferred by the decision maker.     

An application of goal programming to production planning in the crushed stone industry

ABSTRACT

The problems facing the aggragate stone industry in Zambia such as low capacity utilization, failure to meet customer requirements, unnecessarily high operating costs, poor inventory control practices, heavy borrowing and overall poor economic performance are as a result of subjective decision-making related to production planning. This is also true of the industry in nearly all member countries of the SADDC(Southern African Development Co-ordinating Conference) where quarry closures are not uncommon.

As a solution to the problem of production planning and control in the crushed stone industry, this paper presents results of an application of the goal programming technique to a Zambian case study engaged in the production of limestone powder for the chemical industry. The formulation of a mathematical model for handling multiple objectives is discussed. The goal programming model can be used by management as a strategic decision support instrument.

Results of the study show that over time work is related to the levels of demand for each product as well as the capacity utilization of the plant. The conflicts among the various goals of the short term production plan are identified. The study suggests that goal programming can provide an improved model to solve the problem of production planning in the crushed stone industry.     

A robust mixed integer linear programming framework for underground cut-and-fill mining production scheduling

ABSTRACT

A review of general optimization studies that have been proposed for underground mining shows that previous works lack flexibility, operability and practicality in relation to cut-and-fill mining production scheduling. This paper presents a robust mixed integer linear programming (MILP) formulation for underground cut-and-fill mining. The objective function of the model is to maximize the net present value (NPV) of the operation while meeting all mining and processing operational and technical constraints. The MILP model features stope development and extraction sequencing constraints, mining and processing tonnage fluctuation constraints, and extraction duration and active levels control constraints. These features make the model more practical and expandable. The MILP model is verified and validated with two case studies from an existing mine and the results are compared with the actual mining strategy. The comparison shows a 9% to 17% improved NPV in both case studies resulting from mining higher grades and processing less tonnes thereby generating a better cash flow.     

A review of spontaneous combustion studies – South African context

Abstract

One of the challenges in the coal mining industry is self-heating of coal as this can become a problem during mining operations, stockpiling and transportation. This study reviews the mechanism of self-heating, areas of spontaneous combustion, various factors influencing self-heating and different experimental studies to predict its occurrence. The technical control measures applied to minimise self-heating with special consideration to South African coals are also discussed. The distribution and association of unknown materials accelerating spontaneous combustion at different bands within the seam is yet to be studied. A site evaluation of the effects of these parameters is underway.     

Prolog语言在采矿方法选择设计中的应用

针对目前采矿方法选择设计的缺陷，根据人工智能语言Prolog的特点，提出利用Prolog进行计算机编程，从而实现采矿方法选择设计的智能化。     

Development of a 3D geologic model and database for dragline mine planning on a microcomputer

ABSTRACT

There are a large number of variables that must be taken into account for the development of a dragline mine plan. This is especially true for mining in mountainous terrain, where the geology and topography may be complex. As a result, the manual mine planning process can be very tedious and time consuming

An interactive computer package was developed in order to aid the engineer with dragline mine planning on a PC based system. This package employs recent advances in 3D computer graphics and 3D geologic modelling to help with the visualization of the mine plan and to speed up the planning process

One of the main difficulty with the development of mine planning software for microcomputers is due to the limited amount of available RAM (Random Access Memory). This, in turn, affects the speed of information retrieval from the database and the speed of data processing. A compact geologic and mine model and an efficient database were developed to overcome these limitations. These components where then used as the foundation for the development of a total interactive mine planning package.     

Effective modelling for cast blasting

ABSTRACT

There is a need for cast biasing in open pit mining. Although this type of blasting requires higher explosive consumption, the 30 to 40% saving on handling broken muck justifies application of this technique. Based on the HEAVE module built in SABREX, a computer blast simulation program developed by ICI, effective cast blasting for different site conditions can be designed and confirmed by means of high speed photography. Case studies given in the paper confirm the model's ability to make realistic predictions     

An application of closed queueing networks theory in truck-shovel systems

ABSTRACT

Primary applications of queueing networks theory have been in the area of computer systems and computer communication networks analysis and performance. The application introduced here is a steady state analysis of a generalized truck-shovel system in a typical open pit mine. The service time distributions of each activity are assumed to be of a general form. The approach used here minimizes the error of performance parameter estimates of the most saturated service center. The formulation allows one to obtain estimates of systemparameters relatively fast and very close to those obtained by simulation. The relative error of the criticalperformance parameter estimates as compared to those obtained by simulation do not exceed 5%. The output of the model can be used within various optimization schemes for design and operational control of open pit mining systems.     

Practical considerations for developing an automatically driven open pit mining machine: Compact bucketwheel excavator

ABSTRACT

The arc of electronic revolution is here bringing changes to mining technology. The surface mining Industry is keen to be part of this changing environment. Efforts are being directed towards developing automated mining equipment. This paper, using the compact bucket wheel excavator as an example examines the theoretical and practical parameters which must be considered in developing an automated machine.     

Comparison of tripper-spreader combinations

ABSTRACT

In future, the volume of overburden to be dumped will further increase as mining operations have to go down to greater and greater depths in order to expose the mineral deposits to be extracted in open pit mining.

For this reason, the selection of the correct spreading system is becoming increasingly important. Thus, an optimal tripper-spreader combination has to be selected with regard to the actual dumping procedure and the geometry of the dump crosssection.

In order to guarantee economical mining of mineral deposits, despite the increasing costs of overburden removal, the machine system selected must also be examined with regard to its costs, operational safety and availability.

Because of the complexity of the subject matter and the limited size of this paper, this is a contribution only to give a brief overview of the machines more commonly combined as systems and to present their most significant features in terms of type, method of operation, mass and cost effectiveness.     

Continuous mining and direct sidecasting of overburden in small surface mines

ABSTRACT

In all mines the operating costs depend largely on the type and size of the mining equipment. While a standard equipment is most often selected for small mines, considerable savings may be realized if the use of the continuous mining equipment is investigated. To facilitate such investigations, the paper describes the suitable continuous mining equipment, and discusses the mining methods applicable in small mines.     

Arsenic in mine tailings - the Chimo Mine case study

ABSTRACT

Arsenic is an element frequently associated with mining operations around the world. Its long-term stability in mine tailings may be a problem due to its particular chemical properties. It has been frequently observed that arsenic goes into dissolution at conditions where other metals are stable. This paper presents a case study of a tailing site where arsenic has been periodically released. Data collected over a three-year period are presented and analysed. The paper identifies the causes underlying the periodic arsenic release and defines the treatment methods in order to correct the situation.     

New trends in drilling and blasting technology

ABSTRACT

The mining industry is poised on the threshold of some exciting opportunities. It has been realized that the unit operations such as drilling, blasting, excavation, loading, hauling and crushing are interrelated variables in the total cost equation. The development, advancement and utilization of the innovative technologies are very important for the mining industry to be cost effective. In order to improve performance, the drilling and blasting industry is rapidly adopting technology in all forms. In the modem mines it is very common to encounter the latest forms of laser measurement technologies, global positioning systems (GPS), communication technology and computer systems. The developments in the areas of planning and design of blasts, drill monitoring, drillhole deviation, drill machine navigation systems and laser profiling systems have been discussed in this paper. The innovative practices in the areas of bulk loading of explosives, controlled blasting, explosive performance measurement and the evaluation of blast outcome and productivity have been outlined. The role to be played by the electronic detonators in the next millennium to improve blasting efficiency and mining economics has been described.     

Prediction of instability of slopes in an opencast mine over old surface and underground workings

Abstract

Jharia coalfield is a chief storehouse of prime coking coal in India. Earlier,many shallow seams were exploited by surface mining but when this method became uneconomical the mine operators resorted to underground method. However, due to various geotechnical problems, it was not possible to fully extract coal by underground method. Opencast mining is now being planned for extraction of coal locked in partially worked coal seam for ensuring maximum recovery. The major problem envisaged in conducting opencast mining insuch areas will be the stability of slope. In this paper, the technique adopted for simulation of 144 10 thick section of rock mass in equivalent material model is outlined. Old shallow surface excavation upto 33.0 m and later on underground workings were simulated in coal seam II/III. The span of the void was 160 m. An opencast excavation was conducted for recovering locked coal. The behaViour of slopes are reported here.