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By D. W. Blaylock

I. The Lower Kittaning bed is the most important bed in Clarion County from the standpoint of present production, but the Clarion bed has the largest recoverable reserve. 2. Known measured and indicated reserves in all beds, based on a minim thickness of 14 inches and 1,800 short tons per acre-foot of coal in place, are estimated at 1,210 million short tons as of January 1, 1952. Of this total, 790 million short tons is in beds 28 inches and mare thick. Areas in some beds were omitted from the estimate because available data relative to the bed characteristics are too wager for ding an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, they should be added to the total estimated reserves.

Jan 1, 1956

By Andrew Finney

INTRODUCTION The Sacramento Regional County Sanitation District (SRCSD) serves unincorporated areas of Sacramento County, parts of the cities of Sacramento and Folsom, and the cities of Citrus Heights, West Sacramento, Rancho Cordova, and Elk Grove. SRCSD maintains 145 kilometers (km) (90 miles) of interceptors that convey a combined total of 0.6 million meters3 per day (160 million gallons per day) or more of waste-water, with additional miles of sewer interceptors that are scheduled to be built by 2020. Wastewater is conveyed to the Sacramento Regional Wastewater Treatment Plant in the southwestern portion of the County, also managed and operated by SRCSD, in interceptors with diameters as large as 3.0 m (120 inches.) As part of its overall expansion program, SRCSD has constructed a number of major interceptors over the last few years with tunneling methods due to concerns associated with either the impacts of open cut construction in an urban environment (traffic, safety, noise, environmental concerns) or the need to achieve a crossing of a stream, river, or transportation corridor. This paper focuses on a specific issue that affected construction of the Upper Northwest Interceptor (UNWI) Sections 3&4 project, located at the northern limit of the SRCSD service boundary and within the limits of the City of Sacramento. This project involved the construction of 3.2 km (2 miles) of 2.1-meter (84-inch) and 2.4 km (1.5 miles) of 1.7-meter (66-inch) diameter reinforced concrete pipe (RCP) using MTBM, EPBM, and 3.3-meter (130-inch) two-pass TBM methods. The owner elected to install the RCP using tunneling for a number of reasons including a desire to avoid traffic impacts in a dense urban corridor, to minimize disturbance to the neighborhood, and to avoid potential dewatering-induced settlement issues along the western one-third of the project. For the western portion of the alignment the 2.1-meter (84-inch) reinforced concrete interceptor pipe was to be installed using a 2.7-meter (105-inch) earth pressure balance machine (EPBM). No external dewatering of shafts or tunnels was permitted for reasons of concern about settlement, discussed previously. At the intersection of Elkhorn Boulevard and Natomas Boulevard (at the extreme northwest corner of the project) the 2.7-meter (105-inch) EPBM tunneled past a recently constructed 11-million liter (3-million gallon) water storage reservoir, passing within 3 meters (10 feet) of the tank?s shallow foundation while tunneling through clean sands with a shallow groundwater table. The paper will discuss the implemented solution to mitigate additional settlement risk that was developed as a joint collaboration between the owner, CM, designer, and contractor.

By John B. Umhau

[This !m-i~!.al survey giver, statistice.1 data res;?~dirf ~:rimay ard ?eco~- dqr or scmn tin used in thL: United St,ztas by industries an? incluclcz d;ta on stop&apos;ics, ~urchares, ard plnrt losr.c.5. It is :i ml:anwe of consq~tion in terms of fir.is1icd -prcd.~cts nz6.e iry initid ti11 Sabric:,.torc,, that is, aon- cerns that purchzse virc,in zni s~col~d&apos;l~y i.i.5 ti:; 01&apos; tin c;cra.. rav materi,als ar,d co:lrrert them into !ror?ucts such F!: ti:i plz.te, ~lloyr;, and. c?hemic?ls; comy~nias ;~urchn.&apos;.ii~; alloys, ch:rr.ic,~l::, or tin vl?.tc fcr furthcr a:mflzc- ture ?rc: ~-.f>t i~ci~~dcd. Tilit r~lqe:;tionrr::ire submit tod to consunern ar,nt:incd no dofinition of rnr.oncl.:ryr me$.-i; but, ovrirq to ti~i-: a~counti~ procedure used s.l~o~c-:t 1&apos; thu scrnn hac i~-.rtergol:e ch?rri?~ of ovinerzhip or titlo, thc rc!coverod t! n !its b~en i-c<;,r(it.!rj L.S r,e~3r;d:q met.1. Tbv tin content ~f ]

Jan 1, 1938

By David Schroeder, John Chipman

Jan 1, 1964

By F. S. Knoll

Electrostatic separation is one of the most misunderstood physical processes used to beneficiate minerals. Nonetheless, millions of tons of titanium ores, iron ores and other minerals are processed every year economically, efficiently and safely. Over the past ten years major advances in electrostatic separation and its application have occurred. New processes include dewatering clay slurries, separating halite and sylvite, and shape separation of vermiculite and gangue minerals. Electrostatic separation techniques are based on one of two methods, electrophoresis or dieleccrophoresis -- processes involving charged and uncharged particles respectively. In some cases, the combination of these two techniques has proven quite useful. The purpose of this paper is to provide a basic understanding of the physical processes collectively called "electro- static separation" in order to enhance one&apos;s ability to define and consider new possibilities in mineral processing and other fields.

Jan 1, 1984

By D Lozada, A Salazar

Geometallurgy is a tool that, for more than a century, has been present in the implicit operations of mineral beneficiation. There’s a need to understand the characteristics of the material to be processed. This has led metallurgists to ask geologists what type of rock and mineralogy is entering the Beneficiation Plant and vice versa. The geologist needs to understand the beneficiation process in order to be able to carry out the production programming. The paradigm is whether geometallurgy can be applied to small-scale mining or if it is only aimed at large companies that invest millions of dollars to conduct studies. With this work, we provide an example of how geometallurgy can help improve the processes of a small mining company located in Ecuador (South America). We performed characterizations of geological and mineralogical and metallurgical tests in universities and the National Research Institute of Geological Metallurgical Mining. The origin of the theme is based on the fact that gold has been detected in the final tailings. The flotation concentrates meet the standards in terms of the content of economically profitable metals, but this isn’t the case with regards to the percentage of arsenic, which has hindered sales. The hypothesis is: conducting technical and scientific research will optimize the metallurgical process for the recovery of gold and concentrates. The referential framework is the mining geology of the Bella Rica District, current status of the Beneficiation Plant. In the theoretical framework there are parameters of the veins, comminution operations, gravimetric concentration, flotation, and cyanidation. The methodological framework contemplates the characterization of the gold ore, the chemical, mineralogical, textural, metallurgical analysis and the interpretation of the results. Thus, the design of a geometallurgy model of the deposit, with its main characteristics, is a conclusion that serves as a basis for the proposal of the optimization of the metallurgical process.CITATION:Lozada, D and Salazar, A, 2018. Geometallurgy applied to small-scale mining: a case study, in Proceedings 14th AusIMM Mill Operators&#39; Conference 2018, pp 153–162 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By Frederick J. Murrell

No other region of the world is enjoying the tremendous growth of power use that is currently being experienced in Asia. Fortunately for the coal industry — particularly in Asia — the power plants being planned or under construction are designed to use coal as fuel. This has produced a significant increase in the demand for steam coal that, in turn, has encouraged many in the industry to develop new coal mines. Indonesia is a country that has enjoyed substantial growth in coal production. This developing country has 195 million people who live on the nearly 13,000 islands. It has quickly emerged as the third-largest exporter of steam coal, following only Australia and South Africa. Almost all coal in Indonesia is mined by surface-mining methods.

Jan 1, 1996

By Stanley C. Suboleski

1977 was the modern day low point for productivity in the coal industry. At that time, no one could have predicted that the industry was about to enter a productivity rise that would continue unabated through the 1980s. Thirteen years later, the cause of this phenomenon is still not well understood. While many government studies focused on the fall in productivity from 1969 to 1977, none have been undertaken to explain the rise. Some of the likely causes of the gain in productivity during this period will be discussed here. An attempt will also be made to quantify the value of some of the technical innovations that have taken place. The remainder of the gain is assumed to come from non-technical sources. The nature of these sources, although largely non-quantifiable, is also discussed. Since the number of mines that have adopted the technical innovations noted here is largely unknown, the actual contribu¬tion of technological changes to the overall productivity gain can only be estimated.

Jan 1, 1990

By P E. H Gregg, R B. Stewart

Restoration trials established in 1985 included a treatment where pasture seed was sown directly into fertilised tailings. After seven years, accumulated soil data was used to compare physical and chemical changes in the plots with the original tailings control area nearby. &nbsp; A known amount of annual fertiliser additions over the seven year period allowed nutrient balances to be calculated. Losses of S and P were relatively high at 72% of applied S and 28% of applied P. Calculations show that at least 240 kg N/ha/yr was fixed by clovers and this is likely to be under-estimated given that the calculation did not allow for leaching losses.

Jan 1, 1993

By N. Kumar Kittusamy

Operators of construction equipment perform various duties at work that expose them to a variety of risk factors that may lead to health problems. A few of the health hazards among operators of construction equipment are: (a) whole-body vibration, (b) awkward postural requirements (including static sitting), (c) dust, (d) noise, (e) temperature extremes, and (f) shift work. It has been suggested that operating engineers (OEs) are exposed to two important risk factors for the development of musculoskeletal disorders: whole-body vibration and non-neutral body postures. Method: This review evaluates selected papers that have studied exposure to whole-body vibration and awkward posture among operators of mobile equipment. There have been only few studies that have specifically examined exposure of these risk factors among operators of construction equipment. Thus other studies from related industry and equipment were reviewed as applicable. Conclusion: In order to better understand whole-body vibration and postural stress among OEs, it is recommended that future studies are needed in evaluating these risk factors among OEs.

Jan 1, 2004

By L. Cui

A new flotation collector, benzyl arsonic acid, was used for the flotation of ilmenite. ESCA, Auger spectroscopy, and chemical analysis were used to investigate the correlation between the variation in surface constituents and the flotation recovery of ilmenite. Experiments indicated that, as the ratio of surface Ti ions/surface Fe ions increases, flotation recovery increases. pH regulation with an inorganic acid was found to be effective in changing the ratio of surface ions, and, hence, the flotation recovery.

Jan 1, 1986

By L. St-Georges

In aerospace and transportation industries, severe problems are related to fatigue failure. Aluminium is frequently used in these industries to optimize the solidity and minimise the weight of the structures. Nevertheless, the fatigue life of aluminium alloys is limited and specific efforts have to be made to reduce the vibratory stresses in the mechanical parts. When riveted, the life of the sheet metal structures can be increased compared to welded structures, due to the energy dissipated by the friction between the rivets and the sheet metal and the sheets themselves. In the past decade, a new tool was developed to assemble aluminium structures; the friction stir welding. With this new technique, fatigue life of the aluminium welded joints can be increased by a factor from two to ten. However, less energy can be damped by the friction between the components and increased vibratory stresses may occur. In this investigation, the potential of the friction stir welding to create damped aluminium sheet metal structures is evaluated.

Jan 1, 2006

By W. H. Emens

[This circular is one of a series dealing with tie development and equip¬ment of small and medium size mines, and with the costs of such work prior to productive operation. The preparation and publication of these papers by the Bureau off Mines has been made possible through the cooperation of various min¬ing and development companies. The bureau of Mines has published a series of circulars dealing with min¬ing methods and costs at a large number of producing nines in the United States, Canada, Mexico, an, other countries. Unit costs of development work, shaft sinking, (rifting, crosscutting, tunneling, and raising are usually much higher in the preliminary development of a property than during its productive life.]

Jan 1, 1933

By V. R. Degner

The minerals industry trend toward very flotation machines, exceeding 10 m3, began in the late 1960&apos;s and responds to the continuing desire to achieve better plant economics through improved plant floor-space utilization, power requirements, and operational /maintenance manpower heeds. In general, as process design tonnage increases, the benefits of the larger flotation machine becomes more evident. The development of the larger flotation machine can be distingushed from earlier, smaller, machines in demanding a rational "scale-up" procedure to guide the basic design, thereby producing a machine prototype capable of satisfactory-operational evaluation at minimum cost. Proven flotation machine "hydrodynamic" scale-up consideration, successfully applied in the development of both the WEMCO No. 164 (28.3 m3) and No. 190 (42.5 m3) machine will be reviewed, and the resulting economic benefits of large flotation machines in high tonnage applications will be summarized.

Jan 1, 1985

By G. Auld

"A simple method is presented whereby the additional quantity and static pressure necessary to compensate for ventilation duct leakage may be estimated using the circular reference functions of modern spreadsheets. Favourable comparisons have been made to the National Coal Board (United Kingdom) design charts and to a case study analysis. IntroductionIn mining, most ducted systems are applied to the development of access tunnels, and most of these systems leak to some extent. When the ventilation duct fails to deliver the required quantity of air to the work place, there is a significant contribution to the development costs, either directly or indirectly.Directly — More air and more pressure are required to compensate for the leakage, more capital development (ventilation shafts, parallel drives) are required because ventilation systems cannot push the fresh air far enough, and longer re-entry times to ensure toxic blast fumes to be diluted.Indirectly — There is a reduction in productivity because of the inclement atmospheric conditions, and/or closure of development ends because of unacceptable atmospheric conditions at the working place. This has been exacerbated over the last few decades because of the increased use of diesel equipment of ever increasing power, and the more stringent Occupational Health and Safety requirements demanding more air flow per kilowatt of diesel power.The leakage from a duct must, therefore, be reliably estimated in order to assess the effectiveness and construction of the system; assess the effectiveness of the maintenance or repair of the duct; appreciate the cost of the leakage, and therefore apply effective maintenance and installation procedures; and engineer safer, healthier and more cost-effective ventilation systems."

Jan 1, 2002

By Robert M. Koerner

The feasibility of using small-scale models to simulate residential masonry foundation walls subject to fatigue loading was investigated. Five wall segments were modeled in one-quarter scale using dynamic similitude equations. The walls were dynamically loaded using a sinusoidal base motion and wall accelerations were monitored. The stiffness, natural frequency response, and damping characteristics were measured. The number of cycles of testing necessary to cause initial visible cracking was recorded. Analysis of the data indicated the importance of the relationship between the forcing function and the natural frequencies of the structure in influencing cracking damage.

Jan 1, 1980

By H. P. Pew

THE Pembina oil field is in west-central Alberta, about 88 miles west-southwest of Edmonton. The field, about 35 miles long by T HE Pembina oil field is in west-central Alberta, about 88 miles west-southwest of Edmonton. The field, about 35 miles long by 85 miles wide, is the largest in Canada in areal extent, in the amount of oil in place and in the current producing rate. The discovery well was completed in the middle of 1953. The field has grown until its present area is 369,820 acres. There are 74 working interest owners in the field. Early in the producing history of the Pembina field a committee of operators was formed on a permanent basis. The Pembina Operators' Committee has established a permanent staff, which compiles and distributes pertinent field information on a regular basis to all participants. The Alberta Oil and Gas Conservation Board has dealt with field-wide problems primarily through this committee. Expansion of the field was rapid as shown by the number of wells completed -from 135

Jan 1, 1961

Born, March 28, 1853 Died July 23, 1916 On July 25, 1916, the Board of Directors adopted the following minute and directed that it be entered upon the records of the Board & published in the Bulletin of the Institute, and thereof be sent to the family of Mr. Kirchhoff: Charles Kirchhoff was one of the oldest, most widely known and most highly esteerned members of the American Institute of Mining Engineers. On his return in 1875 from a European course of study, to begin a highly successful professional career, he joined the Institute, then just commencing to acquire both national and international recognition. He became at once, and-for more than 40 years continued to be, its earnest , and active supporter, serving it as Manager, Councilor or Director for terms aggregating 9 years,-as Vice-President for 2 years, and twice as President for a year. During the critical period of the erection of the United Engineering Society&apos;s building, and the transfer of the Institute to permanent head-quarters therein, Mr. Kirchhoff was its efficient representative in the United Engineering Society, and on the Building Committee. In 1910, amid the congratulations of colleagues, employees, and innumerable friends, Mr. Kirchhoff retired from active business as Vice- President and General Manager of a great technical publishing company. Yet he sacrificed of his well-earned leisure yet one more year, to serve the Institute as President through 1911.

Jan 9, 1916

By J. Howard Bird

The purpose of this publication is to describe the power-distribution system of the mine and refinery of the Duval Sulphur & Potash Company at Carlsbad, N. Mex. This distribution system has been excellently predesigned to meet requirements and fit special conditions encountered at the property. In presenting the material, the authors point out various features that would be desirable for incorporation in other systems under similar conditions. Central location of switchgear in pressurized vaults and ventilation of such equipment with filtered air prevent salt accumulations and contribute to trouble-free operation. The simplification of power-distribution circuits and overload protection, as a result of centralization of switchgear, the use of individual control circuits enclosed in conduit (which aids troubleshooting), and central location of control panels, are factors which contribute to efficient, safe operation. Those features are applicable to many operations where fire or explosion hazards are encountered, or where dusty conditions may exist, as well as in operations where numerous individual drives are involved.

Jan 1, 1959