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Outline of situations when valuations required - from capital raisings and takeovers, stamp duty, rates and capital gains tax, to probate and litigation between joint venture parties. Definition of types of exploration and mining properties as background to discussion on what methodologies to use (from grass roots to operating mine). Discussion on nature of alluvial deposits in New Zealand and how their characteristics and tonnage/grade uncertainties affect choice of methodology. Assessment of risk factors in New Zealand û technical, financial and socio-political (legislation, access, Maori land rights, environmental). Discussion of appropriate methodologies.

Jan 1, 1992

By George H. Holmes

The water situation in Nevada mineral and related industries is described in this report. It contains information on the sources and adequacy of supply to current operators, requirements and uses, quality and costs, geography, hydrography, precipitation and evaporation characteristics, and Nevada water laws. Also, information is given on the water requirements of one public utility powerplant, and the source and consumption of water in four major cities. Water distribution at 24 operations is shown on schematic waterflow diagrams. The mineral industries of Nevada in 1962 used 8.6 billion gallons of nee' water and reused 3.8 billion gallons for a total usage of 12.4 billion gal¬lons. The copper industry was the major water user. The 1962 value of all mineral production in Nevada was $85.5 million. The large amount of water required to maintain this high production is obtained principally from ground-water sources in alluvial valleys and the permeable rock formations of some mountain ranges. Some water is also obtained from perennial streams and springs. Sources of water utilized by existing industry ore near most mineral industry operations; however, seven companies are forced to pipe water distances ranging from 2 to 8 miles. Although water supplies of presently operating companies are adequate at most operations, several companies resort to large-scale reuse of water as a matter of conservation and economics. Acquisition of water by new operators is possible but takes considerable negotiation. Water rights, surface and underground, are controlled by the State. The quality of the water is satisfactory for most purposes. Analyses of 19 samples, listed in the appendix, show the range in water quality at various plants throughout the State. Costs of delivering new water to current operations range from 2 to 26 cents per 1,000 gallons with an average of 10 cents per 1,000 gallons for power and maintenance. No firm costs for recirculating water were available; estimated costs range from 1.5 to 2.5 cents per 1,000 gallons. The mineral-product value of the entire Nevada mineral industry in 1962 was equivalent to $10 per 1,000 gallons of new water and $26 per 1,000 gallons consumed. Projection of the 1962 water requirements of the Nevada mineral industry indicates that the demand for new water will increase from 8.6 billion gallons in 1962 to 11.9 billion gallons in 1980, a 43-percent increase. Water requirements ill the year 2000 are estimated as 14.8 billion gallons, an increase over 1962 water demand of 78-percent.

Jan 1, 1966

By R. H. Schutz

TO ASSIST users in the selection of reliable and satisfactory respiratory protective devices, the Bureau of Mines bas established five schedules of minimum performance requirements for the approval of respirators. The current revisions of these schedules3 include 13D for self-contained breathing apparatus, 141F for gas masks, 19B and the amendments to 19B for supplied- air respirators, 21B for dust, fume, and mist respirators, and 23B for chemical cartridge respirators. Copies of these schedules may be obtained from the Bureau of Mines, Publications Distribution Section, 4800 Forbes Avenue, Pittsburgh, Pa., 15213. Approval tests on respirators are performed only at the request of the manufacturer4 of the respirator and at his expense. If the device meets the approval requirements, a certificate of approval is granted on the complete respirator. This certificate states that as long as the respirator is manufactured as originally approved, or in accordance with any changes covered by an extension of the original approval, the manufacturer may advertise and sell his respirator as being approved by the Bureau of Mines. Many industries and regulatory agencies require that respirators approved by the Bureau of Mines he used where respiratory protection is needed. The Bureau of Mines, however, has no regulatory power over the use of the respirators that it approves. It acts as an impartial testing agency to insure the availability of suitable and safe respirators.

Jan 1, 1966

By R. H. Schutz

TO ASSIST users in the selection of reliable and satisfactory respiratory protective devices, the Bureau of Mines bas established five schedules of minimum performance requirements for the approval of respirators. The current revisions of these schedules include 130 for self-contained breathing apparatus, 141F for gas masks, 19B and the amendments to 19B for supplied- air respirators, 21B for dust, fume, and .mist respirators, and 23B for chemical cartridge respirators. Copies of these schedules may be obtained from the Bureau of Mines, Publications Distribution Section, 4800 Forbes Avenue, Pitts- burgh, Pa., 15213. Approval tests on respirators are performed only at the request of the manufacturer of the respirator and at his expense. If the deice meets the approval requirements, a certificate of approval is granted on the complete respirator. This certificate states that as long as the respirator is manufactured as originally approved, or in accordance with any changes covered by an extension of the original approval, the manufacturer may advertise and sell his respirator as being approved by the Bureau of Mines. Many industries and regulatory agencies require that respirators approved by the Bureau of Mines he used where respiratory protection is needed. The Bureau of Mines, however, has no regulatory power over the use of the respirators that it approves. It acts as an impartial testing agency to insure the availability of suitable and safe respirators.

Jan 1, 1966

By Clinton M. Young

(Pittsburg Meeting, March, 1910.) I. INTRODUCTION. THE experiments herein. described were carried on in 1908-9 . by the State Geological Survey of Kansas. Some months before taking up work on black powder the Survey had resumed work on an interrupted investigation of explosions in coal-mines, a subject which is engaging the attention. of numerous investigators. An unusual number of serious disasters has directed to. the subject a study which discloses the disquieting fact that, in the. United States, the ratio of lives lost per ton of coal mined has been on the increase. Methods of coal-mining have changed to some extent with the great increase of output, attained in, comparatively recent years. These changes involve the working of very extensive mines, with increased difficulty of ventilation, increased accumulation of coal-dust, and. a very great increase in the amount of explosive used.. . This last point assumes truly startling proportions when it is carefully observed. In the fields of the Middle. West it is not now uncommon for a miner to use six ,kegs (150 lb.) of black powder in a "pay" of two weeks, while within the memory. of men still active, one keg (25 .lb.) would last two men for a " pay." So. great has . the use of explosives become in some fields that the skilled coal-miner is hard to find, and the coal is not mined, but blasted. A preliminary study of the subject. of explosions in coal-mines has. led to the belief . that the use of, large -quantities of explosives, in some cases by slightly-trained men, had not been * Associate Professor- of Mining Engineering, University of Kansas, Lawrence, Ran.

Aug 1, 1910

By M. J. R. Morris

THE year 1939 has seen the iron and steel industry driving for efficiency with unabated zeal. "Efficiency" is here used in the sense of enabling the customer to do more with less, either supplying him with more economically priced steels or with higher priced steels that will do a job more economically. The plain carbon steels have been improved tremendously in quality be- cause of recent control tests. All steel companies have been urged to hold to .closer chemical control, closer standards, soundness, and more control on grain size, and now attention is being directed to closer control of hardening properties. Better control of open- hearth operations undoubtedly will result in an increase in the application of special carbon steel. Further, with a better understanding of quenching, the present trend to study the quenching of this class of steels will be ex- tended. These steels will then be used for purposes to which they are best suited. Utilization of special carbon bars and large shapes seems to be developing less slowly than special car- bon in the form of strip. There are many reasons for this and the future development of this trend will be important. Continued development of the manufacture of parts from strip and sheet to replace forgings, and of formed; structural members such as channels or welded pipe, is notable. Special carbon sheets with nonaging properties have been produced during the year; they maintain a higher degree of ductility over a longer time and are less sensitive to the changes which took place in the former product when stocked.

Jan 1, 1940

By F. C. Harris, S. J. Gaab, J. Sattarvand, S. Duzgun

Underground mines are inherently dangerous due to potential hazards such as fires, explosions, and caving of rock. Although these events are rare, once they occur a speedy and safe egress of mineworkers is critical to survival. Static evacuation systems use exit signs or directional lines but can get obstructed or be hardly visible in smoky or dusty conditions. This paper presents the investigation of the effectiveness of a smart evacuation technology in underground mining, where a real-time guidance system leads individuals on an optimised path to the egress while avoiding danger zones, compared to conventional practices. Participants simulated an evacuation from a virtual reality mine, using the conventional system and the smart evacuation system with real-time guidance. The highest reduction in evacuation time using the smart method amounted to nearly 40% on average. Moreover, 83% of participants preferred the smart guidance system, and agreed that it could enhance safety.

Sep 1, 2021

This list is part of the long-range conservation program of the Bureau of Mines and is intended for use by those interested in the Bureau's publications dealing with oil shale and shale oil. The items included represent 51 years of research by Bureau of Mines employees on oil shale and shale oil and are available at any U.S. depository library. DISTRIBUTION U.S. Bureau of Mines report series contain both free and sales publications. An asterisk (*) designates publications for sale. Such publications can be obtained from Superintendent of Documents U.S. Government Printing Office Washington, D.C. 20402

Jan 1, 1969

By W. D. Bachman

A study has been made of wet, autogenous grinding of disseminated copper ores, including testing of a large number of samples from Kennecott Copper Corporation's Chino mine. The efficiency with which the various samples could be ground was found to vary over an extremely wide range, even among samples taken from different locations within the same ore body. These variations in grindability can be qualitatively correlated with the composition of the rock and the fracturing and alteration that had occurred. Because of the large-scale non-homogeneity of disseminated copper ore bodies, extensive and careful testing of autogenous grinding is needed. An accurate correlation of the grinding data from various samples with the geology of the ore body and with mining plans will indicate if variations in grinding mill throughput can be avoided in practice by mixing or blending of mill feed and if, therefore, autogenous grinding can be applied successfully.

Jan 1, 1970

By John C. Machisak

Injury data and experience, with related employment statistics, at coal mines in the United States for 1960 are presented in this publication under the following general sections: A General injury experience: Tables 1 to 6: Current data on number of injuries, decree of injury, frequency and severity rates, average severity, and related employment and production data by work location. B Selected injury experience: Tables 7 to 38: Current data on principal agencies of injuries, distribution of injuries by part of body injured, days of disability, extent of hand and machine loading, experience by employment and production groups, and various other operating factors and physical conditions related to the occurrence of injuries at the Nation?s coal mines.

Jan 1, 1962

By L. L. Chasko, D. W. Alexander

Researchers from the National Institute for Occupational Safety and Health’s Office of Mine Safety and Health Research conducted an assessment of the effects that ground control mesh might have on rock and float coal dust distribution in a coal mine. The increased use of mesh to control roof and rib spall introduces additional elevated surfaces on which rock or coal dust can collect. It is possible to increase the potential for dust explosion propagation if any float coal dust is not adequately inerted. In addition, the mesh may interfere with the collection of representative dust samples when using the pan-and-brush sampling method developed by the U.S. Bureau of Mines and used by the Mine Safety and Health Administration for band sampling. This study estimates the additional coal or rock dust that could accumulate on mesh and develops a means to collect representative dust samples from meshed entries.

Jan 1, 2014

By Weiran Zuo, Wanzhong Yin, Jin Yao, Keqiang Chen, Qiuyue Sheng, Liu Liu

It is important to investigate the liberation properties of gangue minerals and establish liberation models for low-grade iron ores to reject gangue early. In this study, three types of iron ores from different iron deposits were ground to different particle size distributions by locked-cycle grinding and batch grinding. The liberation distribution of quartz, the most dominant gangue mineral among the three types of iron ores, was tested by Mineral Liberation Analyzer (MLA). Afterward, the liberation distribution of the three types of quartz was fitted using the beta distribution function, and their shape parameters were related to particle sizes to develop the liberation model. MLA test results showed that the liberation distribution of quartz with different grinding methods was basically the same. The developed liberation model predicted the liberation distribution of quartz in low-grade iron ores from different iron deposits well, and its coefficient of determination (R2) was between 0.90 and 0.98. This study deepens the understanding of the liberation rules of quartz in low-grade iron ores from different iron deposits, and on this basis, a more efficient liberation model based on the beta distribution function is developed.

Oct 18, 2023

By Alafara A. Baba, Yakubu A. Dallatu, Kehinde I. Omoniyi, Shemang Y. Chindo, Edith B. Agbaji

As a result of the rise in global demand for pure copper, there is urgent need to consider the processing of low-grade chalcopyrite ores. Ammoniacal leaching solutions have been reported as an effective and efficient leachant for the dissolution of chalcopyrite. This work reports different parameters that influence the leaching kinetics of a Nigerian chalcopyrite-rich siderite ore obtained from Wase Local Government Area, Plateau State, Nigeria, and assayed as 11.30 wt% of Cu. At the optimum leaching conditions (0.4 mol/L NH3-( NH4)2SO4 leachant concentration; 75 °C reaction temperature; 45 μm particle size), the extent of chalcopyrite ore dissolution reached 87.4% within 120 min. The dissolution rate was affirmed to conform to the diffusion control mechanism with the activation energy, Ea, of 38.84 kJ/mol and a reaction order of 0.661 for the leachant concentration being established. The leaching mechanism was affirmed by characterizing the raw ore and the leached product by XRD and SEM-EDS analysis. Ascertaining optimal leaching conditions for copper using alkaline leachant is advantageous from the environment and economic points of view.

Jan 6, 2023

By N. E. Hanna

The current Bureau of Mines active list of permissible explosives includes 124 brands. Thirteen are gelatinous and the rest are the more commonly used granular ammonium nitrate type. The list of permissible blasting devices comprises five Cardox models.

Jan 1, 1965

By N. E. Hanna

The current Bureau of Mines active list of permissible explosives includes 124 brands. Thirteen are gelatinous and the rest are the more commonly used granular ammonium nitrate type. The list of permissible blasting devices comprises five Cardox models.

Jan 1, 1965

By Lawrence H. Roth

Past failures of coal refuse embankments have resulted in more intensified efforts in inspections of coal refuse sites. Inspections, however, are mainly qualitative and time consuming. In August 1975 CH2M HILL was awarded a contract to identify, develop, and test a rapid system for monitoring coal refuse embankments to aid in inspections. The rapid monitoring system developed uses convergent and vertical photography from conventional fixed-wing aircraft. The system was tested on an active landslide and on two coal refuse facilities using both black and white and color infrared film. Field tests showed the system was capable of accurate measurement while providing qualitative data through photointerpretation. The accuracy of the system allows it to be used to monitor coal refuse embankments, tailings dams, major earth dams, and natural slopes. Bibliographies of literature reviews in the area of past coal refuse embankment failures, monitoring instruments and methods, and photogrammetry are included.

Jan 1, 1977

By Michael Hughes, Selva Selvamohan, Ray Costa

"Cutoff walls are commonly used to mitigate underseepage problems for levee remediation projects. At abrupt changes in seepage cutoff wall depths there is a potential for water to flow around the back of the deeper cutoff wall leading to elevated seepage pressures on the landside that could result in exit gradients exceeding design criteria. This condition is referred to as end-around-effects and is a complex problem that requires detailed and time consuming 3-D numerical modeling to represent accurately. This paper presents a simple approach for assessing end-around-effects using the results of 2- D seepage analysis to determine if lateral extension of the deeper portion of the cutoff wall is required. This simplified approach provides a pragmatic solution to a complex 3-D problem. The presented procedure was used as part of the Feather River West Levee Project in Yuba City, California, to assess end-around-effects at 26 locations. The results showed that wall extensions of up to 100 feet were needed at only 2 locations.INTRODUCTIONAs the lead geotechnical consultant for the Feather River West Levee Project, AECOM were responsible for designing levee remediation works for approximately 35 miles of levee protecting the area around Yuba City, California, and communities to the north and south. Due to land use constraints, seepage cutoff walls were the main remediation alternative selected to address underseepage issues for the project.As part of the design review process, the California Department of Water Resources (DWR) requested AECOM to look at 26 locations along the levee alignment where the depth of cutoff wall changed abruptly from shallow to deep, or vice versa. At these locations there was the potential for seepage pressures to pass behind the deeper section of cutoff wall and stress the blanket layer landward of the cutoff wall. A condition referred to as end-around-effects.End-around-effects involve complex 3-D ground conditions that have traditionally been addressed by laterally extending the deeper section of cutoff wall an arbitrary distance based solely on engineering judgment. In discussions with DWR, AECOM developed a simple procedure to provide a more objective assessment of end-around-effects without the need for detailed and time consuming analysis. This procedure allows the engineer to make an informed decision of whether end-around-effects are a problem at the location of a cutoff wall transition rather than laterally extending the deeper section of cutoff wall an arbitrary distance based on engineering judgment alone."

Jan 1, 2015

A newly developed damage model was used in the study of rock fragmentation mechanisms involved in crater blasting. Simulations show that at the detonation of the explosive charge, a crushed zone around the explosive charge is formed due to compressive failure and then a strong pressure wave is sent out forming a pressurized ring that propagates at the dilatation wave velocity. As the pressurized ring leaves the crushed zone, two tensile stress components perpendicular to the radial stress are developed in response to the action of the radial pressure, causing tensile failure and forming a damage zone around the charge. The formation of this damage zone is quite independent of the depth of the explosive charge provided there is no interference by the reflection from the free face. When the pressurized ring reaches the free face, it is reflected there and causes rock failure on the ground surface that forms another damage zone. Under the simulation conditions, it is revealed that the depth of charge is a factor controlling the relationship between the two damage zones. At a depth smaller than the optimum, the two damage zones coalesce into one and there is excessive rock breakage; otherwise, the two damage zones tend to isolate from each other with the increase in the depth of charge. Calculations of fragmentation indicate that the average fragment size increases and the uniformity of fragments decreases when the depth of charge increases as observed in practical blasting.

Jan 1, 1998

Ground and air vibrations induced by large surface blasts have been monitored. These field results, as well as a large number of published results, have been used to assess the performance of existing predictors and for the development of improved prediction methods. Field monitoring has been performed, with four seismographs giving complete wave records, at limestone quarries, coal strip mines and an open pit copper mine. Conventional analysis includes least square fitting of peak particle velocities and peak air overpressures with scaled distance formulations. Frequency content has been analyzed, and correlated with blast design (detonation sequence). Two new methods have been developed for predicting ground vibrations induced by blasting. The proposed analytical predictor accounts explicitly for inelastic attenuation and geometrical spreading, and calculates the peak particle velocity as a function of charge weight and distance. Statistical analysis of case studies confirms the consistent improvement over conventional scaled distance predictors. The second new predictor is a computer program simulating blasts, including blast geometry, charge distribution and detonation sequence, and simulating propagation of individual pulses to any point of interest, where effects are summed. A complete blast vibration results, allowing prediction of frequency content and duration as well as peak velocities.

Jan 1, 1983

By Ralph van Rijswick, Erik Vlot

"Anglo American operates 18 Weir GEHO piston diaphragm pumps (PD) in the two pump stations of the 52-km (32-mile) long Minas Rio iron ore concentrate pipeline. The pipeline is designed to transport 26.5 Mt/a (29.2 million stpy) of concentrate from the mine to the export terminal at the coast.During the commissioning of the pipeline in the fall of 2014, high pressure pulsation levels were experienced, with peak-to-peak levels as high as 20 bar. Based on pressure readings it was concluded that hydraulic resonances were present in the system, which were excited by the third and sixth harmonic of the flow pulsation generated by the pumps.Based on this observation, Weir Minerals Netherlands, manufacturer of GEHO PD slurry pumps, recommended installing a phase shift controller that controls the phase shift between the crankshafts of the individual pumps, thereby minimizing the effect of the hydraulic resonances.GEHO piston diaphragm pumps and pressure pulsation analysisPiston diaphragm pumps are used worldwide to transport abrasive and/or aggressive slurries against high discharge pressures in the mining, mineral processing and power industries. The basic operating principle of a piston diaphragm pump is shown in Fig. 1.A crankshaft is driven by an external electric motor via a gearbox. The crank mechanism transfers the rotating motion of the crankshaft into a reciprocating motion of the piston. The piston displaces a hydraulic fluid, called the propeling liquid, which displaces an elastic rubber diaphragm. When the piston moves to the right, the pressure in the pump chamber drops below the suction pressure and the nonreturn valve on the suction side will open, allowing the pumped fluid to flow into the pump chamber. When the piston moves to the left, the fluid is compressed, and when the pump chamber pressure rises above the pipeline pressure, the nonreturn valve on the discharge side will open allowing a displacement of fluid into the discharge line. The main objective of the diaphragm is to isolate the piston and the drive mechanism from the abrasive and/or aggressive fluid and create a hermetic seal between the pumped fluid and the ambient environment. Piston diaphragm pumps as shown in Fig. 1 are among the largest positive displacement pumps in the world and have been produced with stroke volumes of up to 100 L (26 gal) per pump chamber for flow rates up to 800 m3/h, discharge pressures up to 250 bar and hydraulic outputs over 2 MW per unit (van Rijswick et al., 2010)."

Jan 9, 2017