Two approaches to the computerized planning of dragline operations

There are several approaches to the development of computer programs to aid in the planning of mining operations. This paper examines two such approaches, the use of interactive graphics and expert systems, by reference to a common surface mining problem, planning of dragline operations. The basic rules defining a dragline operation are clearly set out in commercial operators manuals and are predicted by the mine geology and production requirements. The problem tends to require a repetitive arithmetic solution and is ideally suited to the application of computers. In 1983, Manalta Coal Ltd. developed an interactive, graphical program in HP BASIC to run on workstations to solve this problem. The inputs to the program are factors associated with dragline geometry (stored for reference in a dragline database), pit geometry factors such as slope angles and pit widths and the geological structure. The program produces an animated dragline which is manipulated on the screen until the operator has produced a satisfactory solution. The output is a range diagram plotted to screen or to paper and the calculation of factors such as percentage rehandle, swing angles and times. Thus the program stores and retrieves dragline data, automates certain routine calculations and greatly speeds the production of range diagrams. It was designed specifically not to apply any decision making or optimization. The second program uses the features of the Prolog programming language that lends itself to finding multiple solutions and to the application of heuristic rules. The operator selects sets of input values (such as sets of draglines that may be considered) and criteria for eliminating unacceptable solutions. The program lists all possible mine designs that meet the criteria. This program extends the rule base of the operators manual to estimate productivity in terms of bucket size, swing angles, etc. In summary, the first program assists the operator to examine an option in detail and decide on a satisfactory configuration. The second program is intended to find and describe all feasible configurations. The paper discusses the advantages and drawbacks to the two design philosophies and the methodologies involved.