Search

As part of the feasibility study for the development of an open-pit mine at the edge of the Greenland ice sheet, a study is made of the ice flow toward the proposed pit. The flow is analyzed by considering the two-dimensional flow along seven cross-sections. The most favorable profile is determined for each cross-section and its flow calculated. The excavation necessary to expose the ore is 106 × 106 m3 of ice. 66 × 106 m3 of ice will have to be removed in order to establish favorable profiles and an additional 7.9 × 106 m3 of ice will have to be removed each year in order to prevent the glacier from thickening and advancing into the mine. Many other glaciological problems must be considered, and field work continues in order to provide more information about the area.

Land damaged by strip-mining can be restored to multiple and profitable use under the guidance and control of administrative bodies (district governments) on the basis of long-term planning and continuous consultations between mining firms and subsequent users. Through appropriate economic planning and collaboration, land used for open-cast or strip lignite mining can be returned to productive agriculture and forestry, thus realizing the fundamental potential uses of the area for this primary means of production. Land reclamation in the German Democratic Republic provides an example of optimum utilization of formerly derelict mining areas.

Early in 1942 Phelps Dodge Corporation started production of copper from their new open-pit mine and reduction plant at Morenci, Ariz. One of the earliest mining districts of the state, Morenci had produced some 900,000 tons of copper since the beginning of operations in the early 70's, largely from ores of two to three per cent copper content, mined underground.

Surface effects of the Taltal earthquake were comparatively small, probably because of the deep focus, although the magnitude was 7 ¾. Small fractures broke the ground surface along fault zones in the vicinity of Taltal. Minor slumping occurred on a few steep natural slopes and in some cuts and fills along highways. There was minor damage at a few open pit mines. At Taltal, the town most affected by the earthquake, 250 buildings out of a total of 1,100 were heavily damaged.

Nearly all of the well logging devices currently used in the petroleum industry have found some limited application in metallic mineral exploration and mining. However, due to differing problems, the emphasis in the mineral industries has been on those devices regarded as “exotic” or “specialty” by the petroleum industry. These include devices to measure or determine induced polarization, magnetic susceptibility, and, hopefully, nuclear activation and the use of spectral analysis. Problems which the mining industry believes are solvable with well logging methods include bulk assay and recognition of minerals adjacent to and retired from a borehole, delineation of joint and fracture systems, leaching problems which involve porosity, permeability and groundwater movement, bank stability in open pit mines, roof and pillar loading in shaft mines, grindability, and penetration rates in drilling. Devices currently offered by the well logging industry which may be useful for these problems include those capable of measuring electrical properties, natural and induced nuclear radiation, seismic velocities of both compressional and shear modes, temperature, mechanical features of a borehole such as diameter and rugosity, and borehole photography either direct or by television.

In the introductory lecture of this “Course on rock mechanics”, the fundamental differences between the rock properties and the rock mass properties were mentioned. In this lecture, we shall examine more closely, first of all, those engineering properties of the rock masses which require to be determined in our engineering structures. It need not be emphasized that the engineering structure and the geological ground form together a physical system in which the rock or the ground is usually the weaker part, and consequently determines the overall safety of such a system. Only by a correct appraisal of the properties of the rock masses the design of an engineering structure, e.g. tunnels, slopes in open pit mines, will meet the safety requirements and will be economically dimensioned.

A gaping hole at Chuquicamata, in the Atacama desert, provides impressive evidence of man’s efficiency in altering the face of the earth when he applies himself to mining the materials of the crust. I refer, of course, to the Anaconda open pit mine, from which more than 350 million cubic meters of rock have been removed since operations began in 1915. Less spectacular, perhaps, but certainly no less significant as to volume and value of the materials involved, is the stripping of topsoil from the lands of South America, by forces of nature which man has unleashed or aggravated.

The multi-period open pit mine production scheduling problem is formulated as a large scale linear programming problem using the block concept. A solution procedure is developed through decomposition and partitioning of the subproblem into elementary profit routing problems for which an algorithm is presented. Many of the traditional mine planning concepts are discussed and suggestions for improvement through use of the techniques developed in this thesis are given. In the development of the solution procedure, those constraints which govern the mining system are considered as the master problem. The constraints which dictate the sequence of extraction are used as the subproblem. The properties of the single period subproblem and its dual are discussed, and the dual problem is shown to be equivalent to a bipartite maximum flow problem for which an algorithm is given. The Multi-period subproblem algorithm is developed by partitioning by stages and using the properties of the single period subproblem. This treatment allows optimization of the complete mining-concentrating-refining system over the entire planning horizon and permits the system to dictate how and when to process a block of material.

Surface mining machinery has increased in size and power to enable deeper deposits to be exploited economically at high rates of production. Most of these machines are electrically operated and this requires carefully planned electrical distribution systems and supporting services such as an increasing degree of automation to reduce the expensive requirement of manpower, planned maintenance of equipment to reduce the chance of breakdown of machines which with larger machines and an increasing degree of mechanization and concentration can have a catastrophic effect on output and communication.

Approximately 28 single track or 17.5 route miles of electrified railroad constructed for the specific purpose of hauling 30 million tons of relatively low grade copper-bearing ore between the open pit mine at Bingham Canyon, Utah, and the two copper concentrators located at Garfield, Utah, were placed in operation on May 1, 1948.

The purpose of this paper is to demonstrate the use of a Linear Programming model in open pit mine evaluation. The primary conditions to be incorporated into the model are the course and the inclination of the ore vein, and, during the whole life of the mine, safe slope angles to be maintained. Subject to this the objective of running a mine is assumed to be maximizing the direct operating profits which consist of proceeds from the sale of ore minus direct operating cost of extraction, transportation, and upgrading. First the Linear Programming model is developed, and subsequently some computational aspects are treated.

In open-pit mining of lignite, production plans have to be set up for a period of about twenty to thirty years. This is partly due to the close interaction of production plans and investment plans and partly due to legal requirements for open-pit mining in Germany. The major uncertainties encountered in setting up a production plan stem from the geological structure of the pit. The total deposit of lignite in the field as well as the stratification of the layers of waste material and lignite can he considered as stochastic variables. The production plan is formulated as a chance-constrained programming problem. The model requires maximization of a linear form subject to linear and non-linear constraints. In order to facilitate computation of the large-scale problems encountered in practical applications the original model is changed into a straightforward linear programming model. An iteration procedure is derived by which the solution to the original non-linear problem is found. The production plan is computed for different levels of acceptable risk. The results form a risk-profit-surface from which management has to pick the optimum-optimorum plan according to its risk-preference function.