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By A. T. Iannacchione

Recent fatal injuries occurring during pillar retreat coal mining call for better identification of the hazards and recognition of risks. Ground control hazards associated with room-and-pillar retreat mining tend to intensify with depth, requiring extra precautions in the form of additional controls. In many locations these activities are further complicated by local complexities often associated with unique or novel circumstances, such as over-mining or under-mining. One technique recently studied by NIOSH, Major Hazard Risk Assessment (MHRA), may help mine operators to mitigate the risks associated with pillar recovery operations. The approach was trialed at two underground coal mines in southern West Virginia that are currently practicing pillar recovery. The first step in the MHRA process involved reviewing the segments or parts of the pillar extraction mining system and identifying associated hazards and threats to the operation. Some of the high risk hazards at these two sites included: ? Rock fall during pillar extraction covers equipment and injury occurs during recovery operations, ? Rock fall above the roof bolt horizon, potentially injuring ? workers and/or requiring recovery action, ? Rib fall under deep cover, potentially injuring workers, and; ? Strata instabilities associated with subsidence of the interburden due to simultaneously mining two seams in close vertical proximity to one another. The mines? risk assessment teams then considered each threat individually in order to systematically identify potential unwanted events. The top unwanted events were examined individually using structured risk analysis tools. The output from the process includes a list of priority existing controls for monitoring and auditing, and a second list of potential new controls. These controls consisted of: Examples of best practices, ? Enhanced communication, ? Implementing standard operating procedures (SOP), ? Protocols for emergency response actions, ? Effective layouts, ? Efficient monitoring, and; ? Successful audits. This paper documents the process as it unfolded at the two mines, and analyzes the strengths and weaknesses of the MHRA technique as it applies to pillar recovery operations. This work was part of a larger NIOSH research project. NIOSH was responsible for: 1) facilitating the risk assessment process known as Major Hazard Risk Assessment (MHRA), 2) documenting the risk assessment process, and 3) providing mine management with a written draft summary of the risk assessment process. The results of the risk assessment represent the thoughts and opinions of the individual risk assessment teams and should in no way be construed as an endorsement of the risk assessment output by NIOSH or the University of Pittsburgh.

Jan 1, 2009

By M. Quamrul Ahsan, Andrew Griffiths, Edward P. Jucevic

Heap leaching of precious metal ores using the cyanide process is extensively used in the Western U.S.A. for extracting gold. Consequently, the impact of cyanide in the spent heap is closely examined by environmental agencies and permitting authorities. Currently, many states require that all decomnissioned heaps be detoxified before abandonment. This paper describes a case study for detoxification of spent heaps at the ACH-Dayton Project using hydrogen peroxide. The chemistry of cyanide detoxification by hydrogen peroxide, together with simplicity of a detoxification operation, is discussed.

Jan 1, 1989

By Ben E. Lusk

First of all let me say what a genuine pleasure it is to be here. Acapulco certainly is a beautiful change. I'm going to spend sometime talking about change, because frankly I'm astounded at the rate of change in our world today. One good example of this, reminds me that the first time I spoke before the AIME two years ago, we were at the Ramada Inn in Beckley, West Virginia. Today we're at the Princess Hotel in Acapulco, Mexico. Now that's what I call a change. Seriously though, I'm sure you've all heard it said that the most consistent thing about our society is its constant change. Five years ago, no one could have predicted the changes we experienced in the United States during the first half of the 1970's. In the past twenty-four months alone, we have seen two presidents, three vice-presidents and hundreds of administration and government personnel changes. We have stumbled from one social crisis to another, while suffering through rising inflation, major energy shortages and labor unrest that could plunge us into a full scale economic depression. In view of these constant and unpredictable changes around us, it's obvious that we must learn to deal with change and "roll with the punches" if we are to survive. A controversial book published recently, explores in detail the various aspects of change and its impact on man.

Jan 1, 1974

By D. A. Harman

The U.S. Environmental Protection Agency recently recognized Newmont and other mining companies, along with the Nevada Division of Environmental Protection for their voluntary work in reducing mercury air emissions. One example of this voluntary effort is the installation of a reactive scrubber to capture mercury vapor from the exhaust of a carbon regeneration kiln at Newmont’s Twin Creeks Mine. After considering the available technologies, a proprietary reactive scrubber, developed by ADA Technologies, Inc., was selected and is currently being commissioned. Mercury removal rates greater than 90% have been documented.

Jan 1, 2004

By Wen L. Chen

The steam coal quality is less stringent than metallurgical coal quality. The steam coal is prepared either by cleaning full size range of raw coal or cleaning coarse coal only, leaving the fine coal raw. The latter scheme is more cost competitive. It is particularly applicable to U.S. eastern soft coal where low ash coal is concentrated in fine sizes. For raw coal size separation, a recently developed Rotating Probability Screen, developed by the British Coal Board, may be advantageously used for easy change of raw coal separating size and to avoid screen deck plugging when handling wet and clayey raw coals.

Jan 1, 1983

By David H. Carrillo

HYL has developed a sticking tendency test which accurately predicts behavior of iron oxide feedstocks in the HYL III process. Test results together with pilot plant experimentation and commercial scale demonstrations permit the conclusion that lump ores will not agglomerate at 960°C (1233 K) in an HYL III Plant. Pellets may also be processed without agglomeration at 960°C (1233K) with the addition of no more than 5 percent lump ore. Using the HYL III process, the ironmaker can exploit feedstock market conditions without sacrificing plant productivity or energy efficiency.

Jan 1, 1981

By Robert O. Vernon

Urban sprawl, and all its attendant problems, is upon us. In Florida, and much of the rest of the world, this has been intensified by a special problem - the coastal zone - a land of high-intensity urbanization localized where the sea and our citizens interact. Florida is blessed by a long coastline of beautiful beaches, indented by estuaries, lagoons and spring fed rivers. Rocky and sand covered islands invite habitation. A large and varied fauna and flora make recreation an avocation and work a pleasure. Accompanying these people are all the sustaining, and satellite industries that find the climate, labor, and commodity markets, cheap water transportation, and natural resources to be attractive. It is estimated that by the year 2008 a megalopolis will stretch down the Atlantic Seaboard from Georgia to encompass the Keys and extend along the Gulf to Alabama. This city will be fenced by the sea on one side and by the water management works, necessary to provide the water supply for this complex, on the other. What can we do about increasing the amount of water available for this population and decreasing the resultant wastes??? Rarely has there been tendered a more favorable opportunity for a coordinated planning and development project that will provide public access to beaches and multiple use of the coastal lands. Florida, as a peninsula swept by ocean breezes, having a largely indigenous water supply and only the beginning of the pollution of estuarine and coastal waters can cope with air, water and coastal dissipation and pollution, if we have a beginning at providing a constant water supply and at limiting pollution. This answer would appear to lie underground, where the porous limestones are interbedded with impervious fine-grained sediments and ground-water that circulates through these aquifers empty to the ocean and Gulf along the continental slopes.

Jan 1, 1969

By Frank F. Rahne

Butler Taconite, operated by the Hanna Mining Company, is an Iron ore pelletizing operation that is located on the Western end of the Mesabi Iron Range in Northeastern Minnesota. The operation mines low-grade taconite ore and through primary crushing, two stage grinding, magnetic separation, agglomerating and indurating, produces 2.6 million annual tons of high quality, 66% iron pellets. Mining and stripping is done with 13 - M100 trucks and 5 - 12 cu. yd. shovels. The operating processes in the concentrator and pellet plant are primarily con¬trolled through a centralized control room and monitored by a PDP l140 computer. During 1969 and 1970, a re-organization of the Company took place. Through this re-organization, each mine unit was analyzed and studied to determine the proper staffing of the internal departments. At this time, it was decided to continue with further detailed studies of the Maintenance Department with the intent to reduce maintenance costs. Maintenance costs at the time of the re-organization were 38.6% of the total mine operating cost. The preliminary study indicated that the Maintenance Department had a system of maintenance, as a matter of fact, it had a separate system in each sub-maintenance division and in some of the sub-divisions each foreman had a system of his own. Therefore, from the data collected, it was decided to develop one system of maintenance that could be utilized throughout the entire operation. To determine the type of system suitable to all phases of the operation, detailed time and method studies were conducted. All types of maintenance tasks performed at the operation were studied. The data collected was analyzed and the recommended improved methods were reviewed with the Maintenance Superintendent and his staff. The new improved methods that were accepted as feasible, were introduced into the system immediately.

Jan 1, 1975

By B. K. Parekh

Economical dewatering of ultra-fine (minus 74 m) clean coal slurry produced in column flotation to a 20 percent or lower moisture level will be an important step in successful implementation of the advanced fine coal cleaning processes. The main objective of the present study was to evaluate efficiency and effectiveness of three dewatering techniques, namely, hyperbaric, vacuum and screen bowl centrifuge, in dewatering of ultra-fine (D50 -25 m) clean coal slurry produced by the 'Ken-Flote' columns operating at the Powell Mountain Coal Company, St. Charles, Virginia. he hyperbaric filter using 3 bar pressure and 1650 cake formation angle, provided a filter cake with 23.6 percent moisture with a throughput of 800 Kg/m2-h and air consumption of 868 Nm3/t (460 scfm/t). The vacuum filter with 30 percent submergence provided a filter cake with 27.8 percent moisture with a throughput of 122 Kg/m2-h. The screen bowl centrifuge provided a dewatered product containing 32.9 percent moisture at a feed rate of 450 Kg/hr, however, the solids capture was only 65 percent. Addition of 1 Kg/t of a cationic surfactant provided filter cakes with 19.1 percent, 23 percent, and 34 percent moisture using hyperbaric, vacuum, and centrifuge, respectively. Similarly, addition of 0.5 Kg/ton of copper chloride lowered filter cake moisture to 20.7 percent and 24.8 percent, using hyperbaric and vacuum. With the centrifuge no improvement in filter cake moisture was noted. However, use of 80 Kg/ton of 'orimulsion' in the centrifuge provided dewatered product containing 26 percent moisture, and the solids capture increased from 65 to 95 percent. The dewatered product appeared dry and was easily handleable.

Jan 1, 1999

By A. A. Wallach

During the early design stages of the San Manuel Concentrator, numerous questions were raised concerning the required slope for tailings pipelines. The tailings disposal area which had been selected was so situated, that an average down-slope of 5% existed. A gravity tailings disposal system was to be designed and it was necessary to determine the optimum pipeline slope for design purposes. This information was also necessary to determine the life of the available disposal areas before tailings pumping would be required. At approximately the same time as this problem arose, it was reported that a concentrator in the southwest was having considerable operational difficulties due to periodic plugging of tailings lines. These factors combined made it seem desirable to conduct some sort of test work which might give information concerning the flow characteristics of the tailings to be produced, from the San Manuel Concentrator. It was felt that the maximum information could be obtained if a tailings line could be erected which would allow for varying slopes, varying heads and accurate measurement of pulp velocity. A five-foot Denver Agitator was installed on a bank overlooking a cut for a rail- road track. Approximately 160 feet for new &-inch pipeline with victaulic connections was installed on low trestles along the track, with provisions made for varying the slope of the line by use of accurately constructed sets of shims, A valve discharge was installed on the tank so agitated pulp could be run into a standpipe at controlled volumes. This standpipe was 10 inches in diameter and approximately 5 feet high. A 4-inch nipple welded into the side of the standpipe approximately one inch from the bottom was connected to the 4-inch pipeline. At the discharge end of the 4-inch pipeline a launder arrangement was so constructed that the entire discharge could run into a pump sump or into 50-gallon measuring vessels. In normal operation the flow was from the agitator to the standpipe through the pipeline into the pump sump and from there pumped back to the agitator tank.

Jan 1, 1958

By D. A. Saint Don, M. Prueher, S. Barnwell

With the current changes in technology, multiple methods are now available for aggregate resource identification. From Sonic to Coring, Reverse Circulation to Percussive, there are many choices to make regarding drilling technology. The discussion will outline the methods above with focus on aggregate investigation and highlight the new technologies that will make a difference in your search.

Jan 1, 2004

By T. W. Camm

"Search Amazon.com using the keyword “leadership,” and you are rewarded with a list of over 144,000 titles. There is no shortage of books and articles, many of them well written, with excellent ideas. So why is there still a constant cry for effective leadership in organizations? Often, the person in charge has personal blinders that prevent them from seeing or understanding how to implement the newest leadership idea or method. Either deliberately or subliminally, there is a disconnect from learning about leadership, and actually modelling and implementing what has been learned. Some current research in leadership theory can provide insight and tools to address this issue. INTRODUCTION Let’s start with a discussion of terms. Pseudo is defined by Webster (2015) as “Being apparently rather actually as stated.” Synonyms include affected, assumed, contrived, fake, false, phony, pretended, and artificial. Antonyms for pseudo provide additional clarity, especially when we consider terms normally associated with effective leadership: genuine, natural, unaffected, unforced. A similar type from my world of academia is a pseudointellectual, “A person exhibiting intellectual pretentions that have no basis in sound scholarship” (Dictionary.com, 2015). This is a person pretending to have an interest in intellectual activities for status; a fraudulent intellectuality. The thought of applying the term pseudo to leadership first occurred to me while reading Power and Innocence by Rollo May (1972). In discussing the dynamics of power, and how the innocent are often victims of the exercise of power, especially the more aggressive and destructive types of power, he saw two types of innocence. The first he called authentic innocence, which he described as a childlike clarity that carried into adulthood. The second type he called pseudoinnocence, a type of naïveté that makes a virtue of powerlessness, weakness, and helplessness; being more childish than childlike (p. 48-50). Just as there is the potential for pseudoinnocence and pseudointellectuals, it is also possible to experience pseudo leadership. (I hope the gentle reader is not troubled by my decision to use pseudo leadership as two separate words, in contrast to the use of compound words for pseudoinnocence and pseudointellectual cited above. Since there is no official definition of pseudo leadership, I have exercised my author’s prerogative to treat it as two words, both because I think in this particular application this makes the most sense, and also I think it is easier to read). As we will see, there are numerous theories applied to leadership. What is so troubling to many of us in organizations, there are a myriad of “leaders” in companies espousing pet theories, but very few instances where the actions of these individuals match their words. This is a particularly important problem when we look at the effect this has on the day to day operations of a mine, and where effective leadership (or its absence) can have a profound impact on both productivity and safety."

Jan 1, 2016

By Nenad Spoljaric

Greensand, greensand marl, and green earth are names given to sediments rich in the bluish green to greenish black mineral known as glauconite. The word glauconite is derived from the Greek word glaukos, meaning bluish green. The term "greensand" as a rock name for a glauconite-bearing sediment is more appropriate than "greensand marl," a term that has been doggedly perpetuated in the literature. Because of its potash and phosphate content, greensand was mined and marketed as a natural fertilizer and soil conditioner for more than 100 years. The advent of manufactured fertilizers with adjustable nutrient ratios led to a decline in the use of greensand in agriculture. The material has since been recognized as useful in water treatment. Unfortunately, despite large reserves and world- wide distribution, glauconite has not been utilized to any significant commercial extent because no major application has been found for a substance with its chemical composition and properties. This is probably due mostly to a paucity of research on its potential commercial uses. Extraction of potash received considerable attention during and just after World War I. Because of relatively high extraction costs and a generally low potash content (viz., less than 8%), glauconite lost its appeal as a source of this commodity. Historical Background Greensand was used as a fertilizer in New Jersey in the latter part of the 1700s. During the early 1800s its use became more common; applications of as much as 22.5 kg/m2 were sometimes made, although recommendations for agricultural use suggested 4.5 to 11 kg/m2 (Tedrow, 1957). Many crops, especially the forage type, were said to improve with greensand application; however, because of its slow release of potash, large quantities were required. Certain greensands that contain sulfur and sulfide minerals are harmful to plant growth, and these were classified as poison, burning, or black marls. The availability of higher grade potash salts from other mineral sources and the manufacture of prepared fertilizers displaced the agricultural use of greensand during the latter 1800s. During the mid-1800s the greensand industry, centered in a small section of the eastern United States, grossed more than $500,000/y. Toward the end of the century, however, annual production had dwindled to less than $100,000 in value. By 19 10 there were only six or eight greensand producers grossing less than $5,000/y each (Tyler, 1934). There was a brief revival of the US industry during World War I because of the curtailment of foreign potash, especially from Germany. During the latter 1940s and early 1950s greensand was again recommended as a food nutrient for plants and farm crops. Agronomic studies discussed its potential as a soil additive that gradually releases potash and many trace element nutrients essential for plant growth (Tedrow, 1957). Greensand was sold with the idea that it would condition soil and absorb and hold water while its base exchange properties would release trace elements. For a short time glauconite was used in certain parts of New Jersey as a binding additive in the brick industry, and in the 1800s it was used for making green glass (Cook, 1868). In the early 1900s the base exchange properties of glauconite were recognized for water treatment and the mineral gained acceptance as a water softener. Mansfield (1922) does not mention base exchange even though this phenomenon was known in 1916 or earlier. From 1916 through 1922 several patents for the use of glauconite as a water softening agent were granted. A method was also patented for treating greensand to improve it for water softening and ready regeneration with common sodium chloride brine (Borrowman, 1920, Spencer, 1924, Kriegsheim and Vaughan, 1930). Treated glauconite, on contact with water containing magnesia or lime, takes up magnesium or calcium ions and releases sodium ions. This exchange is limited to the outer surface of glauconite grains, and when all the surfaces have absorbed their capacity, the grains must be regenerated. Regeneration, simply stated, consists of treating or backwashing the glauconite with a sodium chloride solution, which replaces the hard water elements with sodium, thus reviving the glauconite. The process has become more sophisticated due to competition among companies in the water softening business. Greensand products for water softening generally consisted of several different grades distinguished by the particular treatment the glauconite was given during processing. The standard greensand water softener was produced from natural glauconite that was only washed and classified. Its characteristics for water softening are given in [Table 1].

Jan 1, 1994

By Roussos Dimitrakopoulos, Liam Findlay

Semimobile in-pit crushing and conveying (IPCC) systems can help reduce truck haulage in openpit mines by bringing the crusher closer to the excavation areas. Optimizing a production schedule with semimobile IPCC requires integrating extraction sequence, destination policy, crusher relocation, conveyor layout and truck fleet investment decisions. A mining complex with multiple mines and IPCC systems should be optimized simultaneously to find an optimal schedule for the entire value chain. An integrated stochastic optimization framework is proposed to produce long-term production schedules for mining complexes using multiple semimobile IPCC systems. The optimization model has flexibility to select the crusher locations and conveyor routes from anywhere inside the pits. The framework uses simulated orebody realizations to consider multielement grade uncertainty and manage associated risk. A hybrid metaheuristic solution approach based on simulated annealing and evolutionary algorithms is implemented. The method is demonstrated using an iron ore mining complex

Nov 1, 2024

By George M. Potter

Precious gold and silver markets support substantial activity in the search for and development of improved and unconventional ore and tailing processing methods. The need for such methods 1s strengthened by consideration of increasingly low grade and refractory ores and old tailing reserves. As background for this review of new and unconventional precious metal processing, recent USBM data (1981) show annual world gold production of about 40.8 million troy ounces. In the U.S. about half the 2.8 million ounce consumption was used for jewelry and the arts, 39 percent for industry, and 8 percent for dental purposes. World silver production in 1981 was about 365 million ounces. Domestic usage the same year was about 117 million ounces. More than $ was used for photography and 30 percent for electrical and electronics. By process, about 1 percent of U.S. production of gold came from amalgamation, 66 percent from cyanidation, 31 percent from smelting ores and concentrates, and 2 percent from placers. As for silver, about 11 percent is from cyanidation and 89 percent from smelting ores and concentrates. Evidently the search for innovative and unconventional precious metal processes must include gravity concentration, froth flotation, hydrometallurgical, and electrometallurgical methods. Although smelting processes are equally important, they largely comprise nonferrous metal technology, and are not discussed here.

Jan 1, 1984

By E. G. Loesche

Grinding mills in which the comminution takes place between rollers and the surface of a disc, table or ring are generally known as roller type mills. The Loesche Mill, also known as the Disc Roll Mill, is a special type of roller mill in which the grinding surfaces consist of two rollers assembled over a horizontal disc or table which rotates at a relatively low speed. This design is particularly applicable to industry's present day demand for large capacity grinding mills.

Jan 1, 1964

By David A. Rice, Scott A. Shuey, William K. Tolley

The U.S. Bureau of Mines (USBM) is developing new dewatering technology to permit the recycling of iron values contained in wet steel plant sludges. In laboratory tests, Q-BOP fume sludge was dewatered to 12% moisture by displacing water with acetone in a plate-and-frame pressure filter. Acetone is reclaimed through distillation at lower cost than conventional thermal drying of the sludge. The projected additional energy requirement for acetone treatment of the sludge, including acetone recovery, is $5 to $7 per dry ton.

Jan 1, 1995

By Brian E. Davies, Bobby G. Wixson

INTRODUCTION The mining, extraction and refining of metals into useful materials is an honorable profession with an ancient and productive history. Civilizations have long depended upon metals for their implements, structures and machinery necessary for survival, growth, and development. Today, as in the future, metals and minerals are essential to the progress of mankind as we approach the 21st century with technologies and concepts that will require new concepts and production from the metal mining and processing industries. Today is the tomorrow we talked about yesterday and the implementation of new ideas is essential if we are to achieve "Frontier Technology in Mineral Processing". Unfortunately, the state-of-the-art mining, processing, smelting and refining methods historically employed were less than desirable environmentally, which has caused todays public to view the metal mining and processing industry with concern. Presently the ancient rock and chat tips connected with old Roman lead-zinc mines which were worked in Wales are causing stream contamination problems that must be corrected at considerable expense to the local governmental agencies (Firth, J.N.M., et al., 1981). However, improved progress has been made and the environmental control and clean-up procedures utilized by modern lead-zinc operations in the "Viburnum Trend" or "New Lead Belt" of South East Missouri may serve as a model to illustrate how alternative technologies, environmental concerns and cooperative efforts contribute to efficient mineral production within the confines of a U.S. National Forest region without significant environmental impacts. This area received international attention when it was opened within the boundaries of the Clark National Forest in the mid 1960's. By 1970 it ranked first in the world by producing 432,576 short tons of lead ore and has since continued in this position producing 451,153 short tons of lead ore in 1983 representing 91% of the total United States lead production (U.S. Bureau of idines, 1983). This production comes from a mining area approximately 40 miles long by 10 miles wide extending in a north-south direction. Geologically the lead is disseminated throughout the Cambrain age Bonneterre Formation, mostly a dolomite, at depths ranging from 700 to 1200 ft. (213.4 to 365.8 m). Galena (lead) is the principal ore mined with lesser quantities of sphalerite (zinc), chaleopyrite (copper) and silver being recovered as economic co-products. This new mining development in one of Missouri is most scenic areas could have led to a classic confrontation between industries and environmentalists. Instead, through the cooperation of industries, governmental agencies and university researchers, the Ozark environment has been protected, and may serve as a model for future coexistence of the mineral industry with the environment. Cooperative Program Development As early as 1965 five new mines and two lead smelters were being prepared for production and environmental concern was an essential part of that planning. All the mining companies became acquainted with representatives of the various federal and state agencies and scientists from the University of Missouri-Rolla (UMR). During the next six years, St. Joe Minerals Corporation, American Metal Climax, Inc., Cominco American Incorporated, Ozark Lead Company (Kennecott) and American Smelting and Refining Company participated in cooperative research efforts. The companies also participated in information exchange meetings, the development of improved analytical methods and the utilization of research findings in the modification or construction of pollution-abatement facilities. Early on research was carried out to determine background values and to establish natural baselines of trace metals in the surrounding environment. The unusual topography and drainage pattern of the mining area were helpful since it was possible to establish control sites and test sites below individual mine-mill operations to study waste-water effects on the receiving streams. The location of the ‘New Lead Belt', mines, mills,

Jan 1, 1985

By G. Brooker

The back-filling operation at Olympic Dam mine supports a 9.8 million tonne per year (Mtla) underground Longhole Open Stoping operation. It involves a combination of Cemented Aggregate Fill (CAF), Surface Rockfill and Underground Rockfill. The fill material is introduced from the surface via bore-holes into the top of the stopes. Due to the deleterious effects of the dust and the thickness of the atmosphere in the stope it is not possible to view the filling process. The need for a means to measure the filling process is driven by the stopes, which have both rock and CAF fill placed in them. The large volumes and high relative cost of CAF makes the minimization of CAF fill a business priority. Incorrect filling can lead to the sterilization of ore reserve. The use of millimeter wave radar to view through the haze to give real-time data on the relative positions of the different fill masses is being developed as an in-stope fill control device. This paper reviews the salient points of the technology and its potential use in the back-filling operation at Olympic Dam. The broader potential of this technology for use in the mining industry by 'seeing' through water and dust laden environments such as that found in stopes and ore passes is discussed.

Jan 1, 2001

By K. F. Unrug

Extrapolation of the rock properties obtained from the cores exploration holes to the surrounding areas often causes problems because of frequent sudden changes in the geologic composition of strata. To address this problem, the author has been developing a method of rapid strength testing "in situ," with application of a borehole penetrometer. This method, as opposed to conventional laboratory testing, does not require rock samples to be retrieved and handled/machined before testing. The results are generated by strength determination on the wall of a drill hole at a site. The newest development is a borehole penetrometer that requires only a 1.38.mm (1.5 in) diameter hole. The small diameter of the penetrometer body allows for drilling test holes with production mine equipment such as roof bolters. It opens the possibility of broad application in coal mines, as well as in hard rock mines and tunneling. The principles of the apparatus are described and are illustrated with examples of its applications.

Jan 1, 1999