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By J. J. Moore

Combustion synthesis or self propagating high temperature synthesis (SHS) reaction systems are discussed with respect to thermodynamics and kinetics. In particular, tile effect of the process parameters, ego particle size, AHf, ignition and combustion temperatures on these self sustaining reactions is discussed. Combustion theory is used to investigate the effect of the overall activation energy of the SHS reaction on the combustion front propagation rate and in obtaining a clearer understanding of the transition from stable to unstable propagation. Finally, examples of the application of combustion synthesis to advanced materials processes are made, in particular the synthesis of Ni-Ti -X intermetallic shape memory alloys, TiC-Al2O3 and ZrB2 ?Al2O3 ceramic composite materials.

Jan 1, 1991

By D. Hong

The leaching behavior of rhenium in ammonium iodide solutions with iodine as oxidant has been studied. Experiments were carried out in an autoclave. The effect of stirring speed, temperature, pH of the solution, iodine and iodide concentrations on the dissolution of rhenium was investigated. It was found that high temperature and high pH of the solutions were essential for the efficient leaching of rhenium. The dissolution rate was found to be dependent upon the concentration of iodine and iodide. It was concluded that the dissolution of rhenium under the conditions studied was controlled by mass transfer of iodine with an apparent activation energy of 15.77 kJ/mole.

Jan 1, 1997

By Richard B. Muter

In determining the layout or combination of unit operations to be utilized in a modem preparation plant, several factors must be taken into account. Among these are the washability data, size consist data, the particular market or markets for the coal, the mining method used, the degree to which the coal must be prepared, expected fluctuations in raw coal and markets, and the overall economics of the process. In addition, there are the health and safety aspects of coal utilization and preparation. Chapter 1 of this book discusses the characteristics of coal and coal markets, while Chapter 2 deals with the design of preparation plants. Once the unit operations for a particular plant have been decided upon, these arrangement may be depicted by using a flowsheet. A coal preparation plant flowsheet is a two-dimensional graphical representation of the sequence of operations, the arrangement of machinery, and the flow of materials for a particular coal cleaning operation. The flowsheet is usually qualitative in nature, becoming more quantitative as material balances, water balances, numbers and sizes of various pieces of equipment, etc. are added. The usual convention in preparing a flowsheet is to show the feed flowing from left to right, starting at the top left and working down as in an all-gravity process. Various symbols are used for each unit operation as depicted on a flowsheet, and Fig. 14-37 is a compilation of the commonly accepted international standard symbols for each unit operation. Fig. 14-38 through Fig. 14-40 are flowsheets of various coal cleaning processes as published in the January 1976 issue of Coal Age. Each process has its own unique features which, among others, depend upon the coal being cleaned, the coal market, and the mining operation. Fig. 14-38, for example, is a flow diagram for a jig plant preparing steam coal from two strip mines located a few miles apart. In addition to the jig washer, cyclones are used to treat the finer size coal. Fig. 14-39 is a flowsheet of a heavy media plant using a heavy media washer for + %-in. (+6.3-mm) coal, froth flotation for -28 Tyler mesh (-0.6 mm) material, and dewatering phase units (dwp) for Y, in. x 28 Tyler mesh (6.3 x 0.6-mm) cleaning of steam coal. In addition, thermal drying, centrifuge drying, and the use of vacuum disk filters and thickeners for dewatering are depicted. Fig. 14-40 is a flowsheet of a plant producing metallurgical coal. In addition to the heavy media and froth flotation circuits, a tabling circuit is also employed. These flowsheets are intended to give the reader an example of how the various unit operations for coal cleaning may be linked together. Figs. 14-41 and 14-42 illustrate the conversion of block diagrams into an IS0 prescribed set of symbols.

Jan 1, 1991

By Javad Sattarvand, Amin Moniri-Morad

Predicting equipment failure behavior plays a critical role in providing a safe operation. Although various reliability evaluation methods are available for estimating failure behavior profiles, these approaches are based on mathematical formulation, leading to actual operation simplification and improper estimation of failure trends. This study proposes a discrete-event simulation (DES) approach to model fleet failure behavior. This approach can model the maintenance strategies in multi-component systems with minimum simplifications. In this regard, the first step was to collect a historical failure time dataset (e.g., the time between failures). Then, the DES model is established to predict the severity of failure events and design maintenance strategy considering actual operation circumstances. Afterward, the maintainability analysis was performed to estimate equipment downtime and availability. The achieved results showed that the system availability was about 85%. Also, the findings demonstrated that the DES could efficiently predict the equipment failure behavior using various stochastic events.

Jun 25, 2023

By Craig J. Brown

Despite its great potential utility, ion exchange has only achieved limited application in hydrometallurgy. To a significant extent this is due to the limitations of conventional ion exchange process design as well as the properties of the ion exchange resins themselves. Over the past decade several new ion exchange resins have been introduced with properties that make them potentially very useful for various hydrometallurgical separations. In addition, a novel ion exchange process called Reciprocating Flow Ion Exchange or Recoflo, which has been employed in the metal finishing industry for the last dozen or so years for chemical recovery and effluent treatment, has been shown to offer a number of unique and significant advantages over conventional I.X. technology.

Jan 1, 1984

By E. A. Córdova

Current methods for scratching a piece of rock to obtain or check the characteristics of its component material can sometimes be expensive and time consuming. Scratching a rock core requires an object with a point that it is capable of sliding along the surface of the rock while recording the response from the rock due to the sliding. With the idea of providing a cost efficient solution for a scratch device, a new generation turntable arm, composed of a cartridge with a diamond stylus and a USB output connection to the computer, was used to record the vibrations from the sliding of the stylus along a rock core surface. The output sound from the stylus was captured with the computer as an audio input signal. The raw sound data was recorded in a standard waveform audio format (wav) file, and post-processed using sound spectrum analyzer software (Spectra-Lab) to capture numerical data such as frequency, amplitude, and noise from the file. The results for frequency, amplitude, and noise were compared and plotted against the scanned surface of the rock core in the search for correlations that might represent specific characteristics of the surface being scratched.

Jan 1, 2010

By C. A. Rawlins, P. Rostami

"Ventilation systems are not only an integral part of any underground mine design but are a significant contributor to the mine’s capital and operating costs. The ventilation and cooling design systems presented in this paper were part of the prefeasibility evaluation of an underground platinum mine in South Africa. The mine would ultimately operate at the depth of 1,200 m below surface with a proposed 4 Mtpa production rate. The proposed mining operation is a highly mechanized operation using diesel equipment. Significant daily production rate, large amount of equipment and expansive nature of the operation, contributed to a challenging while flexible ventilation design requirements. This paper presents how to safely and efficiently optimize capital expenditure and operating costs associated with the mine air cooling and refrigeration system through practical ventilation design practices. Successful capital and operational savings by modulating installation and commissioning of refrigeration facilities can influence the economic realization of such systems. The adapted planning and design approach provided a cost-effective advantage while complying with design safety and regulations. INTRODUCTION This paper outlines a prefeasibility evaluation of the heat loads and related cooling system to be employed at the proposed platinum mine. The paper also provides appropriate details for a comprehensive understanding of the applied methodology. The proposed mine will be a trackless underground operation using a combination of mining methods. Initially, ore zones with vertical thicknesses greater than or equal to 18 m will be mined using the long-hole stoping (LHS) method, while thinner ore zones will be mined using mechanized drift-and-fill or drift-and-bench methods; hence, a highly mechanized operation with LHDs, trucks, drill rigs, personnel carriers, etc. is envisioned. Broken rock (ore and waste) will be transported by the means of trucks to the main passes (ore and waste) and collection points. Mining zones identified in the project occur at depths ranging between approximately 700 m to 1,600 m below surface. Primary access to the mine will be via a 1,100 m deep, 10 m diameter production shaft (named Shaft No. 2), three additional shafts will be sunk to provide future ventilation and production support. Three main access levels are established as primary haulage levels and include a series of interconnecting ramps. Additional mining sublevels will be developed as necessary. Figure 1 shows the proposed shaft locations and main access levels in a 3-D elevated view. Mining is performed using highly productive mechanized methods. For this reason, an annual ventilation estimate is based on requirements for mobile equipment (i.e., 0.06 m3/s/kW). The air requirements imposed on the underground operation is further influenced by equipment heat loads, auto compression, and virgin rock temperature, as the main sources of in-mine heat."

Jan 1, 2015

By S. Mischler, J. Organiscak, S. Klima, C. Seaman

"Researchers at the National Institute for Occupational Safety and Health’s Pittsburgh Mining Research Division (PMRD) performed comparative testing of six hollow cone water sprays from three manufacturers: static swirl chamber sprays from Spraying Systems (BD-3, BD-5) and Steinen-Hahn (SH-3, SH-5), and movable swirl chamber sprays from Repair King (RK-3, RK-5). Water flow testing was completed at three operating pressures (60, 80, and 100 psig) where both sets of sprays (3-series and 5-series) produced similar water flows, deviating less than 8% from the average water flow rate at each pressure. Airflow induction testing was completed at 80 psig using a hot wire anemometer to take air velocity measurements upstream of the spray nozzles. Respirable dust capture efficiency testing was completed in a 14.5-m3 (512-ft3) closed system dust chamber at 80 psig. The dust capture efficiency ranged from 7.2% to 9.9% for the 3-series nozzles, and from 5.3% to 7.1% for the 5-series nozzles. Sprays were also analyzed using a Cloud Aerosol and Precipitation Spectrometer (CAPS), which uses light scattering to count and size the airborne water droplets from each spray. In both cases, Spraying Systems sprays produced the largest mean droplet size, followed by Steinen-Hahn and Repair King sprays, respectively. INTRODUCTION Coal mine worker overexposure to respirable coal dust continues to be a problem in underground coal mining operations in the United States. The U.S. Mine Safety and Health Administration (MSHA) now requires coal mine worker respirable dust exposure to be no more than 1.5 mg/m3 average over the actual working shift (CFR 30-70.100, 2016). Potential overexposure to respirable dust by continuous miner, roof bolter, and shuttle car operators may be prevented if proper safety and health practices are implemented as detailed in the mine’s ventilation plan (CFR 30-75.371, 2016). Water sprays are a necessary component of an underground coal mine ventilation plan. They are important on the continuous mining unit for moving air and removing respirable coal dust from the breathable airstream. MSHA requires underground coal mines to include the number, types, location, orientation, operating pressure, and flow rate of operating water sprays in their mine ventilation plans (CFR 30-75.371, 2016). Water sprays can become clogged, requiring the sprays to be properly checked, maintained, and replaced in order to continue meeting the ventilation requirements described in the mine ventilation plan.In an effort to eliminate the problems with spray clogging, Repair King has developed self-cleaning movable swirl chamber hollow cone water sprays (RK-3, RK-5). The spray’s movable swirl chamber is designed to only open when water pressure is applied to the spray nozzle, preventing the nozzle from clogging. Anti-clogging sprays could improve mine production by reducing the amount of time spent servicing clogged sprays. Also, these sprays could improve health and safety of miners since they would continue to suppress and capture dust and continue to move airflow at the face, while a clogged spray loses this ability until it is cleaned or replaced manually. The objective of this research was to assess the comparability of the Repair King sprays with the most commonly used sprays in underground coal mines using performance criteria. An assessment of the sprays self-cleaning or anti-clogging capability was not conducted."

Jan 1, 2017

By T. W. Beck, J. A. Organiscak

The U.S. National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) has recently studied several redirected scrubber discharge configurations in its full-scale continuous miner gallery for both dust and gas control when using an exhaust face ventilation system. Dust and gas measurements around the continuous mining machine in the laboratory showed that the conventional scrubber discharge directed outby the face with a 12.2-m (40-ft) exhaust curtain setback appeared to be one of the better configurations for controlling dust and gas. Redirecting all the air toward the face equally up both sides of the machine increased the dust and gas concentrations around the machine. When all of the air was redirected toward the face on the off-curtain side of the machine, gas accumulations tended to be reduced at the face, at the expense of increased dust levels in the return and on the curtain side of the mining machine. A 6.1-m (20-ft) exhaust curtain setback without the scrubber operating resulted in the lowest dust levels around the continuous mining machine, but this configuration resulted in some of the highest levels of dust in the return and gas on the off-curtain side of the mining face. Two field studies showed some similarities to the laboratory findings, with elevated dust levels at the rear corners of the continuous miner when all of the scrubber exhaust was redirected toward the face either up the off-tubing side or equally up both sides of the mining machine.

Jan 1, 2013

By Guangming Zhao, Nianjie Ma, Demao Guo, Denghong Chen, Yingming Li

Based on the mechanical essence that large-scale plastic failure zone appears in all or part of surrounding rock in soft rock roadway, the numerical simulation method is used to study the rectangular roadway in layered rock strata. It is clarified necessary conditions must be met for soft rock: firstly, the strength condition is that the maximum confining pressure is greater than the uniaxial compressive strength of rock strata. Secondly, the stress environment condition is that the ratio of maximum confining pressure to minimum confining pressure is greater than 3. Thirdly, the angle condition is that The direction of principal stress action enables the plastic zone of weak rock layers to fully develop. At the same time, the quantitative description method of soft rock is given, and the soft rock roadway is redefined. Soft rock roadway refers to the roadway that meets the strength conditions, stress environment conditions, and rock structure angle conditions under certain surrounding rock conditions and in-situ stress environment conditions. After the excavation of the roadway, a large-scale plastic failure can be formed, that is, a butterfly-shaped plastic zone is formed, and the conventional support cannot be adapted. It is difficult to support in engineering. It provides a theoretical basis and engineering analysis method for the identification of soft rock roadway, and the research results have engineering value Soft rock tunnel engineering in coal mines constitutes a vital aspect of soft rock engineering. This field broadly encompasses rock engi- neering concerning large plastic deformations, e.g., soft rock slope engineering and soft rock tunnel engineering. The intricate geological conditions encountered in soft rock tunnel engineering present a significant challenge to support, which has harmed coal production in China. China leads global raw coal production with the annual output of 4.6 billion tons. Annual tunnel excavation supporting this production spans approximately 11,000 km, with over 10% of these tunnels classified as soft rock formations. Soft rock is commonly associated with soft rock tunnels due to their prevalence in engineering projects. However, reaching a consensus on the definition of soft rock has long been an enduring challenge for scholars and engineers. Numerous definitions have been proposed, includ- ing descriptive, index, and engineering definitions. For instance, the International Society for Rock Mechanics defines soft rock based on its uniaxial compressive strength σ ranging from 0.5 to 25 MPa. China's Engineering Rock Body Standards, established in 1994 (GB 50218-94), take a qualitative and quantitative approach to classifying rocks. Rocks are categorized as hard or soft based on criteria such as hammering sound, fragmentation, water immersion effects, and weath- ering degree. Additionally, the integrity of rock bodies is assessed across five categories intact, relatively intact, soft fractured, fractured, and extremely fractured. This classification considers factors like the number and spacing of structural planes, their combination, and the types of structures. Descriptive and index-based definitions fall under the category of geological soft rocks, providing a comprehensive geological perspective on the surface features or strength characteristics. However, these definitions have limitations in engineering practice, which leads to contradic- tions. For instance, rocks with uniaxial compressive strength less than 25 MPa may not exhibit soft rock characteristics if the tunnel is shal- low with low horizontal stress levels. Conversely, rocks with compressive strength exceeding 25 MPa at sufficient depth and high horizontal stress may exhibit soft rock characteristics. Definitions originating from engineering practice have emerged after realizing the inadequacy of discussing soft rocks without considering engineering. For instance, Dong's loose circle theory defines soft rocks as rocks with a loose circle thickness exceeding 1.5 m, which chal- lenges conventional supports. This intuitive definition, widely accepted by engineering professionals, emphasizes the difficulty in supporting tunnels due to extensive damage. However, various tunnel damage poses a challenge in relying solely on the loose circle thickness of tunnels for determining soft rocks. He introduced the concept of engineering soft rocks, which are defined as rock formations exhibiting significant plastic deformations under applied engineering force. Two fundamental mechanical properties of soft rocks are identified the critical softening load and critical soft- ening depth. Rocks below the critical softening load threshold are categorized as hard rocks, while those exceeding it exhibit substantial

Jun 25, 2024

By A. J. Kwitowski

Teleoperation is a technology that can provide significant health and safety improvements in mining, by relocating machine operators hundreds of meters away from the face area. The U. S. Bureau of Mines (USBM) has recently developed a teleoperation system for continuous mining and haulage equipment. This system features near-real-time closed-loop control. A prototype system was developed and demonstrated on the surface. This system could be used in thin-seam applications down to 914 mm. Details are provided on the developed teleoperation system, results of testing, and expected, future applications of this technology for improved safety.

Jan 1, 1994

By A. G. Fonseca

The effects of coal cleaning, coal combustion and flue gas particulate removal systems on the partitioning of 12 trace elements were investigated. This study was prepared to help document the fate of trace elements in modern coal preparation plants and coal-fired utility boilers. The coal cleaning data were obtained from several coal preparation plant operations. The CONSOL 1. 5 MM Btu/hr pilot combustion and electrostatic precipitator (particulate removal system) test facility was used to develop the combustion systems data. A comparison with the very limited amount of published data from utility boilers is presented.

Jan 1, 1993

By R. K. Mehta

Existing acid mine drainage treatment techniques are not remedial In nature, i.e. though heavy metals can be removed from acid mine water, their presence in tailings and large quantities of these tailings tend to increase capital and operating cost for tailing management. This paper presents the results of a series of systematic tests which finally resulted In the development of the "ferrite" process for mine drainage of coal operations at ambient temperature. The role of pH, temperature, quantity of ferrous salt addition and degree of oxidation is investigated targeting the production of high emu spinel ferrites and effluent water complying regulatory standards with respect to Iron. manganese suspended solids and pH.

Jan 1, 1992

By Ihor Kunasz

The high lithium demand forecasted for some high tech applications and batteries for electric and hybrid-electric vehicles, in particular, has sparked increased exploration for lithium, particularly for lithium- and potassium-bearing brine deposits. The latter have generally followed the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) NI 43-101 guidelines on resource reporting, formulated for hard rock deposits (metals and industrial minerals). While a number of the requirements can be appropriately applied to brines, brines are fluids and require a specific analysis leading to a distinct set of reporting requirements. Brines cannot be considered industrial minerals because the various elements occur as ions in a dynamic fluid, rather than being chemically bonded in a solid. Although chemicals are produced from brines, brines have no relation to industrial mineral deposits. This article analyzes the recently released (Nov. 1, 2012) document CIM Best Practice Guidelines for Resource and Reserve Estimation for Lithium Brines, in light of the practical knowledge available from existing brine operations. It recommends modifications to the guidelines, which, if applied in their present format, will result in overstating resources and reserves and mislead potential investors. The CIM Best Practice Guidelines for Resource and Reserve Estimation for Lithium Brines document is generally descriptive and does not fully address the methodology for brine resource or reserve definition. Lithium and other elements (potassium, magnesium) are contained in a fluid, the hydrologic characterization of which should be the principal focus of a brine exploration program. The fundamental requirement in defining lithium brine resources and reserves in a salar is the identification and definition of those formations ? the aquifers ? that will yield brine in a usable quantity to a well, because brines can only be extracted by pumping wells. Fine-grained sediments will never, as required in the summary Table 1, have ?reasonable prospects of economic extraction,? cannot be considered and, therefore, need not be tested. However, the guidelines recommend the collection of solid samples and a high-core recovery for laboratory testing of various sediments instead of focusing on the brine.

Oct 1, 2013

By F. J. Susko

The U.S. Bureau of Mines is using Fourier-transform infrared (FT-IR) analysis to investigate the bonding mechanism which occurs during the dewatering of clay slurries. High molecular weight polymers are used as flocculating agents in these processes. This investigation presents the results of an FT-IR study of calcium-exchanged montmorillonite treated with polyacrylamide (PAM) and polyethylene oxide (PEO). Both thin film and attenuated total reflectance (ATR) spectroscopic techniques were employed to study this clay-polymer system~ Results suggest PAM is adsorbed to the clay via the nitrogen atom of the polymer. A water bridge is involved in the bonding between the clay and PE~. Evidence also suggests that PEO may be adsorbed directly onto the surface of the clay.

Jan 1, 1990

By James D. Cooper

Long range projections of demand for nonmetallic minerals are presented, together with data on the domestic resources which are available or which can be made available to meet the requirements through the balance of the century. Past successes in solving nonmetallic mineral requirement problems are briefly reviewed to illustrate the capability for solving present and future problems of a similar nature. Major problems threatening the future supply of specific industrial minerals are described together with possible methods for assuring the necessary raw materials for future needs. The growing importance of environ- mental degradation, land use conflicts, and other important factors which affect several or all of the nonmetallic mineral industries is covered, and the necessity of planning for efficient and orderly extraction and rehabilitation of mineral deposits is stressed. The present Bureau of Mines methods and tools for long range planning are briefly discussed.

Jan 1, 1969

By James M. Neilson

In contrast to the rather generalized title of this paper, the subject of discussion will deal with two specific cases of sliding in glacial lake clays in northern Michigan. The slides in question occurred on lands owned by the Upper Peninsula Power Company a short distance south of Lake Superior. Slope failure problems have plagued the Company's operations for many years. It is hoped that this paper may provide some insight into the causes and possible mechanisms of clay slides in general as well as providing details of the two slides specifically cited. LOCATION The Upper Peninsula Power Company's Victoria facilities lie in section 29, T. 50 N., R. 39 W., in Ontonagon County, Michigan. The power site is situated on the West Branch of the Ontonagon River, approximately five miles southwest of the town of Rockland and only one mile to the southeast of the old mining location of Victoria. The area lies wholly within the Precambrian Shield and it is geologically similar to adjacent parts of Wisconsin, Minn¬esota, and Ontario. (Figure 1). THE VICTORIA HYDROELECTRIC SITE The Victoria hydroelectric power facilities were constructed in 1930 on a portion of the West Branch where meanders are conspicuously developed. The generating station is actually sited on an abandoned meander at a place where valley widening has occurred. Water is conducted from Victoria Dam through a 6000-foot, 10-foot diameter wood stove pipe - through a surge tank - and into the powerhouse where

Jan 1, 1971

By Michael Murphy, Gamal Rashed, Brent Slaker

Many underground stone mines in the United States operate on multiple mining levels. The effects of interburden thickness, pillar offset between mining levels at various depths of cover, and in situ stress conditions are poorly understood. Pillar offset is the degree to which pillars are not columnized or stacked. In this study, calibrated numerical models are used to examine limestone pillar stability in these conditions. Also, the critical interburden thickness required to minimize the interaction between mining levels is explored. The model results show that there is interaction between numerous factors that control the stability of stone pillars in multiple-level conditions. The highest degree of local pillar instability occurs when pillar overlap ranges between 10 and 70 percent. The highest degree of stability occurs when pillars are stacked.

Jan 1, 2023

By A. Cecala, J. Noll, J. Organiscak

Many underground metal/nonmetal mines are using enclosed cabs on mining equipment to reduce the exposure of miners to diesel particulate matter (DPM). However, some enclosed cab systems may not be meeting their expected efficiency in capturing DPM, which could be a result of inappropriate filter use, cab leaks or insufficient pressurization. NIOSH investigated several types of filters for reducing DPM to determine which type had the best capture efficiency. The laboratory results indicated that a MERV 8 (minimum efficiency reporting value, as defined by the American Society of Heating, Refrigerating and Air- Conditioning Engineers) filter captured about 50% of the DPM, a MERV 16 filter collected 96-98% of the DPM and two HEPA (high efficiency particulate air) grade filters captured over 99% of the DPM. NIOSH also performed a field study to measure the efficiency of two cabs at a limestone mine. The cab filtration systems of a loader and haul truck were found to be over 90% effective in removing DPM, except under certain operating conditions when the efficiency was as low as 41%. A possible reason for the low efficiencies is an open window in the cab, but more studies need performed to obtain a better understanding of the cause and solution of the problem.

Jan 1, 2011

By David A. Summers

In May 1975 the U. S. Bureau of Mines contracted with the University of Missouri-Rolla, Rock Mechanics and Explosives Research Center to develop a Hydrominer modification to a long-wall shearer unit, wherein the rotating pick-laced drums and connecting gear drives are replaced by a water jet cutting head.1 The concept of the water jet cutting head is based on using the high localized energy of the water jets to isolate a slice of coal by cutting a slot under, at the back of, and at the top of the web. The plow blade of the head then advances into the cut and wedges the pillar over onto the conveyor (Figure 1). There were several potential advantages foreseen for the system of which perhaps the most significant were the elimination of coal dust from the working area2 and the ability, with a variation in nozzle geometry, to cut webs of greater depth with a small increase in equipment horsepower. The University initially designed the head, based on experiments carried out in the laboratory, under an earlier Bureau of mines contract. The experiments showed that it was more advantageous to work at a pressure of 10,000 psi with an estimated flow rate of 50 gpm than go to the higher pressures and lower flow rates which have been advocated elsewhere.

Jan 1, 1977