Search Documents

By S. A. Suhler

The detection of hazardous geological anomalies through remote sensing techniques is the subject of current research efforts sponsored by the U.S. Bureau of Mines. In this review, hazardous geological anomalies are discussed with respect to the "view" presented along with potential operational concepts for each technique. The design and development of a borehole radar is described with emphasis on the potential range and resolution capability of the system under realistic underground conditions. Results of field tests at two coal mines and at a hard rock future subway location are presented.

Jan 1, 1978

By George W. Leney

The iron ore industry might justifiably claim to have originated the science of geophysical prospecting. Their use of geophysical methods was probably the first application of these scientific techniques to the search for economic materials although the exact origin is undoubtedly lost in the unrecorded observations of. some prospector experimenting with compasses or bits of lodestone. Since 1879 when Thalen published "On the Examination of Iron Ore Deposits by Magnetic Measurements" these methods have been a standard supplement to other prospecting techniques. However, many of the great ore bodies of the Precambrian iron ranges were not particularly suitable for geophysical work. The ores were oxidized and enriched through leaching of silica so that they were nearly non-magnetic and other physical properties which distinguished them from the wall rocks were largely destroyed. With the gradual exhaustion of these high grade direct shipping ores, and ores that could be beneficiated by simple means, the iron ore industry turned initially toward the importation of similar high grade foreign ores. At the same time, new processes for concentrating lower grade materials were being developed and older ones improved upon. These concentrates' when pelletized produced such important savings in blast furnace hot metal costs that they now command a premium in the iron ore market and have weakened the competitive position of the remaining high grade ores. The ore bodies now being sought are usually unoxidized and frequently they are also metamorphosed.

Jan 1, 1965

By J. Creamer

Pumping plays a major role across multiple process and facility applications in the mining world. Examples include: raw water supply, leach solutions, chemicals, dewatering, and mine drainage, and process water for metal recovery. Mining operations such as grinding, classifying, separating and concentrating minerals all have pumps at the heart of the operations Special purpose pumps such as dewatering, process water and slurry pumps are at the heart of many of these processes. Unfortunately the pumps themselves are often overlooked in terms of energy savings potential as they are often embedded into these sophisticated processes which are the ultimate operational focus.

Feb 23, 2014

By James Lett

The role of pre-conditioning in a caving operation has multiple benefits, ranging from assisting with improved caveability, normalising fragmentation and improving draw point hang-up frequency. At Newcrest Mining’s Cadia Operations, both the Ridgeway Deeps block cave the Cadia East Panel Cave have utilised pre-conditioning using hydraulic fracturing. Seismic response data inside and outside the pre-conditioned volume show the benefit of treating the full caving block. Cadia East has further developed pre-conditioning to mitigate developing seismic hazards associated with major structures (fault-slip events) and managing mine-wide seismic hazards in new caving operations where the potential for large damaging seismic events exists due to high stresses and hard competent rockmasses. A case study reviewing the impact of pre-conditioning to mitigate seismic hazard associated with fault slip is presented. Cadia East operation undertook a targeted hydraulic fracturing program and reduced the overall number of large events as an example of the benefits of pre-conditioning. This paper will review the application of Hydraulic Fracturing at Cadia and discuss the geotechnical and seismological parameters of seismic events that occur within and outside of pre-conditioned rockmass volumes to demonstrate the benefits that Hydraulic Fracturing bring to future caving operations.

Apr 26, 2022

By Raymond K. Will

Computers are becoming increasingly valuable tools in the mining industry as a greater variety of appropriate hardware and software becomes available, combined with greater acceptance by management, Within a given time period an engineering staff can evaluate or design a project to much greater detail and higher accuracy by utilizing computers once suitable programs have been developed. We are all aware that throughout the world the decreasing grade of minerals coupled with increasing waste to ore ratios necessitate larger capacity, longer term mining operations and attendant higher capital costs. Computers can be of assistance in all stages of mineral exploitation, from geologic exploration through mine feasibility studies and design, to marketing and transportation. Because of the high speed with which data can be digested and manipulated by computers, preliminary information from any stage of investigation can be analyzed to assist in further guidance of that stage. By use of preliminary mine feasibility studies, financial forecasts and sensitivity analysis, even information from a far-removed phase such as marine transportation of the product, can help guide the exploration phase to a realistic target.

Jan 1, 1973

By Peter B. Dowden, David T. Cass

A shield on a tunneling machine has two basic purposes. Firstly to provide temporary support in unstable ground, maintaining the integrity of the bore and protecting the operators, and secondly, in conjunction with other sealing devices, to prevent the ingress of water. In any specific tunnel, unstable ground and water may or may not occur together. Further, there are a number of different ground behaviors that may be termed unstable and these must be defined in order to determine the most suitable type of machine. Beyond the shield itself, the cutterhead and the mucking system design are critical in successfully traversing difficult geology. In any but the shortest tunnels, variations in the geological conditions and the requirement of an acceptable advance rate can impose increasing degrees of sophistication in the machine design. In this paper we will review current designs of shielded type machines and their application, and discuss new developments which blend hard and soft ground tunneling technology. We will also indicate that in some conditions, although first impressions seem to favor a shielded machine, in fact an open gripper TBM may be the wisest choice.

Jan 1, 1991

By R. H. W. Chadwick

We in Kennecott are well aware that Alaskans are interested in the progress of our project at Ruby Creek. We would very much like to be able to present you with a final report at this time and tell you about a new mine. I'm afraid, however, that it will be several years at best before such a report can be made. This, then, is an interim report to describe briefly some of our findings to date, and to acquaint you with some of the problems, both geologic and economic, which must 5e resolved favorably before we can talk about a mine. There are several things about this project which make it unusual and interesting to those of us who have been connected with it. Firstly, there is the fundamental importance to Alaska, in the present stage of its economic history, of any undertaking which offers promise of turning a natural resource into a competitive export product. I am sure all of us would get a lot more satisfaction out of having a part in bringing in a new mine in Alaska than we would out of adding another one to the long list in, say, Arizona.

Jan 1, 1960

By C. K. Skokan

Various geophysical tools have been tested over the last eight years to evaluate their usefulness in defining damaged rock zones in an underground facility at the WIPP site in New Mexico. These tools include direct current and frequency domain electrical methods and seismic tomography. The electrical measurements show a "drying rind" to exist around older excavations. Seismic tomography confirms that a rind of lower velocity has developed along walls. In combining these tools, a monitoring program has been proposed to observe long-term changes in bedded salt. Results from the monitoring of electrical data over a 2-year time period illustrate the applicability of the technique in an underground environment.

Jan 1, 1993

By J. D. Miller

The processing of residues derived from various operations in the mining and metallurgical industry for by-product recovery is becoming more prevalent. A principal target for by-product recovery is flue dust produced by conventional smelting operations. Flue dust from zinc smelters has been processed for many years for the recovery of cadmium (1,2). The cadmium recovery technique which consists of a selective sulfation roast, followed by a water leach and zinc dust cementation, produces a lead cake residue (see chemical analysis in Table I), which consists primarily of lead sulfate.

Jan 1, 1975

By V. V. Ershov

Mining geometrical graphic documentation is employed on a large scale in designing and planning of mining operations at all the stages of exploitation. Mining geometrical modelling of mineral grade distribution presents an independent type of mathematical (graphic) modelling. The idea of functional relationship between geological indices being observed, and spicier coordinates is the basis of traditional mining geometrical modelling. Graphic presentation of three independent variables P =f (x,y,z) is confined to obtaining the series of two independent variables functions. Independent variables are presented as topographic surfaces corresponding to plane cross-sections of a deposit. During exploitation of certain parts of a deposit the most reliable geological information is obtained, characterizing regularities of ore distribution in the entrails. This information is, though, not taken into account in goemetrization of the new areas. In this connection dynamic modelling of deposits in the process of exploitation is necessary, i.e. geometrization of the deposits should be dynamic.

Jan 1, 1986

By Eudes Prado Lopes

The Mineral Resource Exploration Company - CPRM - a part-private, part-government concern jurisdictioned to the Ministry of Mines and Energy of Brazil, was founded in 1969 for the purpose of promoting the exploration of mineral and hydric resources throughout Brazil. The political-administrative framework within which it was conceived and created considering that an economic and financial balance to be maintained in all its fields of activity, CPRM set out right from the start to organize itself to perform -three basic lines of action, which can be summarized as follows: As a Service Company, to carry out those services requested by government agencies and by the private sector through of service contracts; As a Mining Company under the Brazilian Mining Code, aiming at supplementing private initiative, not beyond the field of mineral exploration;

Jan 1, 1975

By II Browne

After a decade of high copper prices, major mining companies are renewing their interest in purchasing operating properties and/or development of ore bodies. An existing operation carries with it a history that can present unique opportunities, while a greenfield operation allows for the establishment of a defined culture. Capital investments are distinctly different. A comparison of BHP Copper Robinson Operation, a greenfield property, and BHP Copper Tintaya Operation, a government owned Peruvian property, will provide insights into mining, concentrating and cultural differences between North and South American Operations.

Jan 1, 1997

By J. D. Miller

The effects of operating variables on water transport to the over- flow, classification of hydrophilic particles and the recovery of copper and molybdenum from a low-grade porphyry ore are presented. Recoveries of copper and molybdenum exceeding 90 percent at a grade of 8 percent Cu and 0.2 percent Mo were realized for minus 100 mesh (1 49 µm) material at retention times of less than 500 milliseconds. The rapid rate of flotation and the effective separation of fine particles for an air sparged hydrocyclone appear to be due to directed interaction of particles in a high force field with numerous freshly formed small bubbles. This interaction occurs in the swirl flow developed by the system and is analyzed in terms of collision and induction time phenomena.

Jan 1, 1982

By K. L. Purdy

Electron spectroscopy for chemical analysis (ESCA) was used to determine the-surface characteristics of products from operating Pb-Zn-Cu concentrators on the New Lead Belt of southeast Missouri and pure galena and sphalerite samples treated-with flotation reagents in concentrations similar to those used in the mills. The emphasis was on the action of surface modifiers such as Na2Cr207, starch, SO2, CuSO4 and NaCN in sphalerite flotation and in the galena-chalcopyrite separation. The objective of the investigation was to monitor the relative oxidation states of the mineral and reagent constituents and correlate these surface concentrations and oxidation states with flotation theory and practice. ESCA was able to follow the action of all the modifiers except NaCN. The existence of PbCrO4 on the surface of galena conditioned with Na2Cr207 was verified. The Pb in the bulk PbS-CuFeS2 scavenger concentrate was found to be significantly more oxidized than the Pb in the bulk PbS-CuFeS2 rougher concentrate. ESCA was found to be most useful for investigating the actions of modifiers rather than collectors due to the large amounts of sulfur and background carbon already present on the mineral surfaces. After calibration for the particular chemical system of interest, ESCA can yield semi-quantitative analyses of the oxidation states of many elements (except hydrogen, and helium) present in the outer 10 to 25 A of a sulfide mineral surface.

Jan 1, 1975

By S. J. Schatzel, K. M. Ajayi, E. N. Rubinstein, Z. Khademian

This study simulates the impact of a shale gas well casing breach near a longwall mine. Field studies are conducted to measure mining-induced permeability changes over the abutment pillar of a longwall mine, and a geomechanical model is developed in 3DEC, a three-dimensional numerical modeling code, to predict the aperture of fractures in the overburden at the study site. The predicted aperture values are used to determine mining-induced permeabilities and the results are compared with the field measurements. These aperture values are provided as inputs into fracture flow code (FFC), which generates a stochastic discrete fracture network (DFN) model for the study site and predicts the potential shale gas flow to the mine. Results from 100 DFN realizations are statistically analyzed using the bootstrapping method to compensate for notable variation in fracture geometry. The results show a significant difference between the gas inflow for nearby panels due to increase in the induced permeability during mining of the second panel. The average gas flow to the mine was calculated as 4.72×10−2 m3/ s (49 cfm) for a hypothetical breach at the Sewickley horizon during the first panel mining, 8.97×10−3 m3/ s (19 cfm) for a hypothetical breach at the Uniontown horizon during the first panel mining, 2.16×10−1 m3/ s (458 cfm) for a hypothetical breach at the Sewickley horizon during the second panel mining, and 8.07×10−2 m3/ s (171 cfm) for a hypothetical breach at the Uniontown horizon during the second panel mining. Depending on the mine ventilation system, this could result in methane concentrations exceeding regulatory limits. Hence, these findings provide insights into the potential risk of an unconventional gas well casing breach near a longwall mine under shallow cover.

Feb 15, 2023

By R. V. Ramani

Minerals, together with agricultural and forestry products, are the primary source of wealth produced in the United States. Although the production of minerals requires only a small fraction of the state's total land surface, as compared with either agriculture or forestry (Table 1), mining activities generally are much more disruptive to the land surface, and rehabilitation is more complex and costly. The past 10 to 15 years have witnessed a sharp increase in mineral exploration and mining, particularly coal mining, which has brought with it an increase in conflict over land use and an increase in negotiations for purposes of mineral prospecting and mining. The general increase in the production and consumption of coal and the particular increase in the percentage of coal extracted by surface mining methods coupled with a growing nationwide environmental consciousness have created increased public concern and in some cases outrage over mining activities. Although there is ample evidence to indicate that it is possible to plan for and design mining activities in such a way that they are compatible with other activities and can thus be made a part of a sequential land-use plan, there is a general lack of knowledge regarding the importance of mining as the provider of basic and essential raw materials to supply society's constantly expanding and increasing mineral needs. This lack of knowledge extends to such matters as land and mineral rights negotiations, the character of mineral deposits and minerals, mineral economics, and land-use planning.

Jan 1, 1977

By J. H. Dietz

The electric assist option for diesel-electric trucks can improve truck productivity while maintaining the inherent flexibility of a truck and shovel operation. In addition, the resulting cost reductions offer a rapid investment payback for many mine situations. A review of the present technology and performance experiences verify the projected benefits in productivity and operating cost. New technologies can further improve the productivity/cost scenario.

Jan 1, 1984

By B. Berhe, R. D. Lawrence, J. Hinzer

"The fortunes of mining companies and their implied value are tied to cycles - both economic and commodity – within which they operate. Hence the determination of appropriate future metal prices is one of the most critical factors faced by mineral valuators especially for advanced projects. Price, and hence revenue, is usually the most sensitive input to the valuation model. Empirical studies of past forecasts show that the success rate for commodity price forecasting is very poor. This paper explores various approaches and comments on their strengths and weaknesses. We conclude that careful evaluation of long-term metal prices is a key element and is hardly a luxury that can be left to simple averages or rules of thumb. INTRODUCTION Discounted Cash Flow (""DCF"") analysis, is well suited for the valuation of advanced mineral development assets, for which there are identified mineral resources and some form of economic assessment (Pre-Feasibility or Feasibility Study). The DCF method is also the most commonly used method for determining value for such assets. It provides a means of relating the magnitude of expected future cash flows from profits (or losses) to the magnitude of the initial cash flow (investment) needed for capital expenditures to purchase or to develop an asset for commercial production. The method proves useful in making investment decisions as it allows for the quantification of the Net Present Value (“NPV”), as well as the Internal Rate of Return (IRR) and Payback Period on initial investment capital. Valuation by its very nature is a forward-looking exercise. The DCF method attempts to estimate the NPV of expected future cash flows, by selecting factors that will likely affect future cash flow based on informed analysis. One of the most critical and sensitive factors is the determination of appropriate future commodity prices. “The variables that have the greatest impact on a DCF evaluation are the reserves, the metal prices, and the discount rate.”1 The determination of future commodity prices for valuation purpose or during M&A negotiations is a hotly contested issue. There are a number of analysts, institutions and specialized commercial data suppliers that provide both short and long-term commodities price forecasts. Also, the use of an aggregated mean for all available forecasts, or consensus forecasted prices for valuation purposes is not uncommon. The methods used in making forecasts for each forecaster may vary and in many cases may not be publically disclosed. Nonetheless, the aggregated mean of all forecasted commodity prices of reputed institutions is usually taken to “represent the market’s view of likely future commodity prices.”"

Jan 1, 2016

By Gerald A. Zicg

The Sheep Creek project area lies between 15 and 20 miles north of White Sulphur Springs in west central Montana, on the southern flanks of the Little Belt Mountains. The Sheep Creek project is a joint venture in which Cominco American Resources, Inc., has a 50% operating interest and BHP-Utah International, Inc., has a 50% participatory interest. The property consists of over 40,000 acres of leased fee land and lode claims. Modern exploration of the Sheep Creek area began in 1973 and 1974, when Homestake Mining Co. examined the extensive Sheep Creek gossans with soil sampling, trenching, and drilling. Cominco American Inc. began exploration in the area in 1976. Between 1978 and 1985, Anaconda Copper Co., Exxon Minerals Co., and Freeport also conducted exploration programs in the area. In 1985, Cominco completed consolidation of the district, gained BHP-Utah International, Inc., as a joint venture partner, and the joint venture drilled the first significant copper mineralization on the property. Of six bodies of copper mineralization so far located, the best defined are an upper copper zone, which includes a probable resource of 4.5 million metric tonnes grading 2.5% Cu and 0.1 % Co, and a lower copper zone which includes a possible resource of 4.5 million metric tonnes grading 4% Cu. Exploration drilling of the property is in progress.

Jan 1, 1991

By V. F. Hollister

The Ivanhoe district, Elko Co., Nevada, is located in the northern part of the Carlin trend of epithermal gold-deposits, but it differs from most mines in the belt in that Ivanhoe epithermal gold ores are found in 14 m.y. old Tertiary volcanic rocks as well as in the better known Paleozoic sediments. Within the Ivanhoe district U.S. Steel (USX Corp.) discovered and partly developed an epithermal gold deposit largely hosted by Tertiary rocks that, with a 167-hole program, was found to contain an open ended probable reserve of 4.0 million tons of heap leachable open pit oxide ore averaging .042 opt Au. An additional 4.0 m.t. of open pit sulfide ore averaging .048 opt Au were also developed. The U.S. Steel orebody was a blind discovery in that it just barely outcropped, and it was found by drilling through a premineral but barren cover of altered Tertiary volcanic rocks.

Jan 1, 1988