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By R. V. Ramani

"In Part 1 of this paper, published in the August 1995 issue of Natural Resources Forum, a review of several mining disasters around the world established the complex nature of their causation and their catastrophic effects. The involvement of human beings, either through acts of commission or omission, was highlighted. In Part 2, a discussion of the various approaches to disaster control, mostly as practised in the USA, is presented. A systems approach to disaster prevention incorporating elements of hazard identification, mine design, emergency response and post-emergency audit is presented.In the USA the role of government in the affairs of its citizens is continually growing. This role is intended to ensure an unimpeded pursuit of happiness and prosperity by the population and to curtail actions which are restrictive or harmful to the citizenry. The passage of a legislation is an indication that it has been decided through the established process that the activities covered by the legislation should receive appropriate consideration. The enactment of the Coal Mine Health and Safety Act of 1969 (The 1969 Coal Act), the Mine Safety and Health Amendment Act of 1977 (The 1977 Mine Act) and the Surface Mining Control and Reclamation Act of 1977 (The 1977 Surface Mining Act), was specifically intended to further the role of government in the health, safety and environmental affairs of the mineral industry.Currently, the federal government's responsibilities for mine safety and health are divided among three agencies: the Mine Safety and Health Administration (MSHA) in the US Department of Labor, the Bureau of Mines (USBM) in the US Department of the Interior and the National Institute for Occupational Safety and Health (NIOSH) in the Department of Health and Human Services (National Research Council, 1981). MSHA is responsible for issuing and enforcing mine safety and health regulations, for training miners and for responding to mine emergencies. The Bureau of Mines is responsible for conducting research on mine safety and on the technological means for reducing health and safety hazards in mines. NIOSH conducts research relating to miner health, and together with MSHA, tests and certifies devices used to detect hazardous materials in mines and protective equipment used by miners. NIOSH also plays a public health role in that its activities in mining include health hazard evalua¬tions, general mining surveillance as mandated by law and medical surveillance including coal miner X-ray and autopsy programmes. MSHA shares with the Bureau of Mines the responsibility for integrating R&D results into operational practice. MSHA implements R&D results either by incorporating them into its own operations or by rule making that requires new practices or equipment to be adopted by the mining industry. In many instances, the Bureau's R&D results have been adopted by the mining industry without rule making."

Dec 1, 1996

By M. Cai

"It is well known that Peak Particle Velocity (PPV) plays a critical role in triggering rockburst damage in burst-prone underground mines. To estimate the PPV distribution around excavations, advanced numerical modeling can be used. In wave propagation numerical modeling, velocity field is often assumed to be uniform around an excavation. However, it is observed that wave velocities near mine openings are not constant, but rather non-uniform. Wave velocity in a rock mass depends on many factors such as rock quality and confinement. In particular, confinement has a large influence on wave velocity. The confinement around an excavation is low at the wall boundary and increases gradually and reaches a constant value far away from the excavation boundary. Hence, stress redistribution due to excavation will have a profound influence on wave propagation in underground mines. A better understanding of the influence of excavation effect on wave propagation helps to interpret the field observation of rockburst damage and improve mine safety. For this purpose, a non-uniform velocity model need to be constructed and the influence excavation effect should be taken into account in numerical wave propagation modeling.In the present study, a non-linear velocity model is developed firstly by considering the influence of confinement on wave velocity. This model links wave velocity to confinement explicitly. A coupled numerical method is then developed and used to study the seismic wave pattern around excavations in underground mines. Two codes, FLAC and SPECFEM2D, are coupled in the analysis. The motivation of developing the FLAC/SPECFEM2D coupled approach is to take merit of each code, such as the stress analysis capability in FLAC and the powerful wave propagation analysis capability in SPECFEM2D. The coupling process is realized through three steps: (1) static stress redistribution around an excavation is analyzed in FLAC; (2) data for coupling analysis, such as non-uniform velocity field (based on the new developed velocity model), mesh, absorbing boundaries, etc., are generated by FISH functions in FLAC and passed to SPECFEM2D; and (3) wave propagation modeling is performed in the SPECFEM2D considering a fault-slip seismic source. Because stress redistribution around the excavation is considered, non-uniform velocity field for the SPECFEM2D model can be obtained and this is a notable feature of this study. Very large difference in the S-wave response in these two modeling approaches with uniform and non-uniform velocity fields can be seen from the modeling results.Using the FLAC/SPECFEM2D coupled modeling approach, accurate velocity models can be constructed and this in turn will help to produce accurate PPV distribution around the excavations. Accurate PPV contours can be used to identify high rockburst risk zones for improved dynamic ground support strategy."

Jan 1, 2015

By A Harding, M Chappell

Precast concrete segmental linings have enjoyed widespread use around the world, and are the lining type of choice for tunnels constructed using a shielded tunnel boring machine. However, there is significant variation in the design of such linings from one country to the next in such areas as materials, geometry, fixtures and fittings, waterproofing and reinforcement to name but a few. This arises because the speed at which the technology has developed within some countries and regions has sometimes outstripped the transfer of such technologies to the rest of the world.This paper provides some insights into the variations in lining design in different parts of the world with the aim of providing designers and constructors alike a reference for the different methods adopted. It provides a context for these developments by briefly summarising historical reviews of this subject before looking at some of the developments around the world over the last 15–20 years. The developments are presented with some reference to the reasons for implementation, and the advantages and limitations commented on. Following on from this description of the state-of-the-art, the authors also provide their own views on what developments we may see in this area in the near future.CITATION:Harding, A and Chappell, M, 2014. Precast concrete segmental tunnel linings – the state-of-the-art, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 257–266 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Axel Pankewitz, Andrew Smith, Mathias Stender, Christian Behrens

"Particle size measurement is one of the most important factors in obtaining peak performance of the mineral processing plant in order to ensure efficient milling and flotation circuit operation. Off-line particle distribution analysis technologies only allow an infrequent check of the ore slurry size and hence do not allow for timely process monitoring or intervention. Most existing on-line particle size analysers suffer from a variety of disabilities such as poor statistics, non-representative sampling or mechanically complex setup. This paper will describe an Ultrasonic Extinction based method which overcomes many limitations of existing online analysers and has proven its performance for mineral applications over many years. Installation examples will be given. Since new technologies usually raise e questions about comparability and agreement to common particle size analytical methods e.g. sieving or laser diffraction analysis, extensive studies were performed comparing these different technologies to quantify the quality of results as well as its mathematical robustness."

Jan 1, 2014

By F. J. Sotillo

"Scrubbing both horizontal (drum) and vertical (attrition) are considered simple unit operations in the beneficiation of phosphate ores. In general, the operating conditions are fixed at high solids content based on the experience of the engineering or equipment manufacturing company responsible of designing this beneficiation step. Nevertheless, scrubbing is a complex unit operation designed to clean the surfaces of phosphate mineral particles of slimes, break loose weak inclusions or attached particles of impurities, and break aggregates of clayish material. Therefore, it is considered that as high solids content as possible should be used to enhance particle-particle interactions (impact and rubbing) without taking into consideration the rheology of the system. However, scrubbing unit operations design requires studying the balance between the increase of particle-particle interactions with the cushion effect that may occur when slimes, clays and fines decrease the availability of free water increasing the apparent viscosity of the phosphate slurry up to that of a paste consistency. This paper presents data from laboratory tests to determine the best operating conditions for the design of these unit operations based on the highest P2O5 grade obtained with the lowest impurities for different size fractions. INTRODUCTION In the beneficiation of phosphate ores, unit operations such as horizontal scrubbing (drum) and vertical scrubbing (attrition) are considered simple unit operations. Therefore, little attention is given to the design of horizontal and vertical scrubbing during the basic engineering studies, and the detail engineering stage, the manufacturers recommending “standard” units and operating conditions based on their experience. Due diligence of several beneficiation phosphate plants at industrial scale indicates that a deficient scrubbing of the phosphate ore results in significant problems in downstream unit operations, such as classification, clarification, gravity separation, magnetic separation, flotation, dewatering, and filtration. Scrubbing is in fact a complex unit operation designed to clean the surfaces of phosphate mineral particles of slimes (clays and fines), break loose weak inclusions or attached particles of impurities, and break aggregates of clayish material. Two phenomena occur, the particle-particle interaction (impact and rubbing), and the rheological effects of releasing significant amount of fines into the slurry. Therefore, high solids contents are recommended to enhance the particle-particle interactions, which may result in a change in the rheological regime of the system due to the slimes, clays, and fines decreasing the availability of free water. This increases the apparent viscosity of the system up to that of paste consistency resulting in a cushion effect that suppresses scrubbing. Under these conditions, not all fines are release and rejected (deslimed), downstream unit operations being affected by the release of clays, resulting in P2O5 losses."

Jan 1, 2017

By Ramana G. Reddy

Thermodynamic modeling and experimental study on impurity capacities and their distribution between mattes or metal and slags in smelting, converting and refining of non-ferrous metals was discussed. A brief review on the recent developments in copper smelting and converting is presented. The analysis showed that, copper smelting capacity increased by a factor of 10 since 60's, smelting rate increased by a factor of more than 5 and process fuel equivalent decreased by a factor of 2. A thermodynamic model for prediction of impurities capacities in slags and their distribution in mattes and slags was developed. The impurities capacities (i.e. sulfur and arsenic) of slags were calculated a priori with no adjustable parameters using the Reddy-Blander model. The capacities predictions were made in a wide range of matte and slag compositions, Pso, and temperatures in conditions pertaining to copper and lead industrial slags. The calculated results for sulfide and arsenate capacities are in good agreement with the available experimental and industrial copper and lead industrial slags data. The sulfide and arsenate capacities in copper slags (fayalite, ferrite and olivine) and lead slags are reviewed. The application of RB model predicted ratios of 02 and S2 partial pressures in industrial copper smelting processes are discussed. Application of this model for the prediction of Sb, Bi and other impurity capacities and their distribution ratios in mattes or metal and slags, in industrial smelting and refining processes is discussed.

Jan 1, 2003

By David L. Veith

This report summarizes a Bureau of Mines review of selected literature on the effects of subsidence due to high-extraction underground coal mining on farmland areas. The data are presented for consideration in evaluating the subsidence effects due to similar mining techniques on the prime farmland areas of Illinois. In Illinois the ground water level in the glacial drift is only 2 to 15 ft below the nearly flat to gently rolling ground surface. The main subsidence concern is flooding, as caused by the lowering of the ground surface, and the subsequent effects on crop production. Positive drainage must be maintained in the farmlands, and the need exists for extensive regional planning by the mining and agricultural industries to maximize short- and long-term production from both efforts. The Bureau is cooperating with the State of Illinois to develop basic information necessary for such planning.

Jan 1, 1987

By G W. Wilson, M Aubertin

A desulfurised tailings cover was installed at the Detour Lake Mine in Ontario, Canada, to reduce oxygen penetration into the underlying sulfidic tailings. The cover ranges from one to 1.5 m in thickness and was intended to maintain high water saturation to reduce oxygen diffusion and consume oxygen by oxidation of the residual sulfide minerals. The tailings impoundment was instrumented to measure climatic parameters, water levels and water content profiles within the tailings and single-layer cover. One year of monitoring data was collected. Additional tailings samples were obtained for geotechnical and geochemical characterisation. The average grain size of the cover material was found to be coarser than the underlying tailings. Monitoring also indicated that air entry values of the cover material were lower than the tailings. Numerical modelling was conducted on the cover to predict water content profiles under varying climate conditions together with the depth of oxygen penetration and diffusive oxygen fluxes. Estimates of the diffusion coefficient and kinetic oxidation rates from field data compared well with values obtained by laboratory measurements. Numerical simulations indicate water saturations of less than 85 per cent can be expected under varying climate conditions. Predicted oxygen flux rates through the desulfurised cover over tailings with high acid potential indicate low flux rates reaching these tailings due to either consumption of oxygen by residual sulfur within the cover or saturation of the underlying tailings.

Jan 1, 2003

By Paul Armstrong

THE first discovery of lead and zinc ore on Calumet island was made in 1893 by John Lawn, who then staked a portion of the property now owned by Calumet Mines, Limited. His discovery was developed by James and Calvin Russell, who are said to have shipped a few tons of sorted ore, averaging 39 per cent zinc, 13 per cent lead, and 11 oz. silver per ton. In 1898, the property was being operated by the Grand Calumet Mining Company, who mined and shipped, for treatment in a Belgian smelter, 1,100 tons of ore averaging 32 per cent zinc, 9 per cent lead, and an unreported content of gold and silver. After some indecisive exploration by an American syndicate in 1907, the property lay idle until1910, when the Calumet Metals Company-later reorganized as the Calumet Zinc and Lead Company-re-commenced exploration. After sinking an 85-foot shaft-the McDonald shaft-and doing a few hundred feet of drifting and cross-cutting, this Company, in 1912, erected a 150-ton daily capacity gravity-concentration plant, in which some 800 tons of ore, mined from the McDonald shaft and Bowie pit, were milled. Owing to very disappointing mill recoveries, the property was shut clown and-after several years of idleness-in? 1916 the mill and mining plant were destroyed by fire and the Company went into bankruptcy. In 1918, an unknown operator shipped to an Omaha, Nebraska, smelter 22 tons of ore, probably sorted from the dumps of the Ste. Anne shaft and Galena pits, averaging 44 percent lead, and 0.26 oz. gold and 61 oz. silver per ton. The British Metals Corporation (Canada), Limited, in 1926, optioned the property. They unwatered the McDonald shaft and, after doing an additional 300 feet of cross-cutting and drifting on the 85-ft. level, estimated there were some 33,000 tons of ore between this level and the surface. Surface exploration, including trenching, on other showings on the property gave discouraging results and the option was dropped.

Jan 1, 1941

By Ernest Bohnet

Each mining operation is unique in some aspect ownership; ore body location, size, geometry, grade, mineralogy, hydrology, or geotechnical parameters; or constraints such as environmental regulations. However, all mining operations are alike in one aspect; the prime objective of any mining project is to maximize the return on the investment. This is the golden rule, or in the language of mining, the investor?s law of conservation. A mineral resource, by definition, does not become a minable reserve unless the mineral or minerals can be extracted economically (and legally). The three preceding sections have covered the various types of surface mining options. The choice of the most economic method is dictated primarily by the type of de-posit to be mined, the mining rate, and the physical characteristics of the deposit.

Jan 1, 2008

By T Bookless, J Pownell, D Meadows

The ever increasing trend of the gold price has meant that ore deposits that were previously considered too complex, or unattractive by virtue of their low gold grade, are now being investigated more closely. These ore deposits present a greater risk of failure than previously was the case. To ensure that the risk of project failure is reduced and the maximum value is derived from the deposit, its mineralogy, as well as other characteristics, should be well understood such that the optimum process can be designed.Quite often the flow sheet design is assembled using individual process components, from various sources, and without consideration of the complete system. Test work programs require careful planning and an open viewpoint in terms of comminution circuit design particularly with respect to ever increasing power costs across the globe. As an example, high pressure grinding roll (HPGR) technology in many cases offers better mineral liberation than the more traditional comminution devices and it does so at a reduced energy input, and yet HPGR test work is often restricted in its scope due to the perceived novelty of the technology and the resultant lack of generally agreed and accepted test work routes.In this paper the authors outline a typical HPGR test work process route driven by the needs of different ore types and illustrate that to optimise the project value, any test work program should start from the premise that thorough understanding of the ore is vital.CITATION:Bookless, T, Meadows, D and Pownell, J, 2013. Enhancing project value through a designed high pressure grinding roll test work program, in Proceedings World Gold 2013 , pp 291-300 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By G. R. Luster

In most current practice, the methods that are employed in technical evaluations of cement raw materials are deterministic; i.e., decisions among alternative raw mixes and alternative plant designs are reached with the aid of only "average" compositions and "representative" samples of the available raw materials. Nevertheless, cement plants are sensitive to raw-material variability, and uniformly high-quality raw materials are not so abundant as they once were. Some simple examples will illustrate how geological techniques can be combined with geostatistical and operations-research approaches to customize mining and processing systems to deal with variable raw-material compositions.

Jan 1, 1987

By S. H. Logan

Mr. B. Neilly: A week or so ago the Secretary was good enough to forward me an advance copy of this paper by Mr. Logan and it was suggested that I comment on it at this meeting. At that time I was not very certain that I would be here, so I committed my thoughts to paper. As a matter of courtesy to Mr. Logan, I sent him a copy of my proposed remarks and I would like to give you just what I sent to him. Appreciating fully Mr. Logan's ability and many sources of information, one naturally hesitates to question anything seriously set forth as his considered opinion. Neither does one of my political stripe like to accuse him of being too 'conservative.? However, in places his paper reminds me of another general manager of a Canadian bank. While I was still Secretary of the Ontario Mining Association, this general manager wrote asking for our forecast on the current year's mineral production, stating that he proposed to refer to such production figures in his annual address to his shareholders. The request was considered very complimentary to the Ontario Mining Association and, in my opinion, justified a great deal of serious study and effort. Finally, the estimate was prepared and forwarded, showing a modest increase over the previous year's total. Picture our surprise and chagrin on reading his address to find that he predicted not an increase but, if you please, a decline of over $10,000,000. Before I cooled off I wrote asking the basis of such a prediction and got a reply to the effect that men in his position had to be ultra conservative in picturing the future.

Jan 1, 1931

By R. Vernon Helm

Four tables listing values for the various physical properties of those sulfur compounds most likely to occur in petroleum and petroleum products are given herein. The data necessary to bring the first compilation2/ in this subject up to date are given in table I -Revised and Additional Data, which includes boiling points, refractive indices, densities, and freezing points. Tables 11-, III, and IV are published for the first time and include refractive indices for the F, C, and G' lines of hydrogen and the helium D:3 line; surface tensions and viscosities, and refractivity intercepts, specific dispersions, specific refractions, and parachors. The need for information concerning the sulfur compounds in petroleum is becoming-more urgent because of the necessity of refining larger quantities of high-sulfur crude oil to meet the rising demand for petroleum products. For a number of years the Bureau of Mines has been engaged in research to make available more information concerning the properties of the sulfur compounds in petroleum. The petroleum industry has recognized the value of such studies, and as a result the American Petroleum Institute has established Research Project 48A to study sulfur compounds. The investigations under this Project are to be done in Bureau of Mines laboratories as a cooperative project in connection with the work already started.

Jan 1, 1949

By Yukio Ishikawa

Sumitomo Metal Mining Co,. Ltd. (SMM) has been producing 22,000 t/y of electrolytic nickel at Niihama by nickel matte electrorefining process since 1970. Although the matte electrorefining is an established process and the productivity has been greatly improved in the last 20 years, SMM has intensively developed the chloride process for the nickel production since 1970's. The nickel and cobalt refining process involving solvent extraction and electrowinning from the chloride solution has been successfully developed for the treatment of the mixed sulphide in 1975. The first application of chlorine leach to the anode slime has been succeeded since 1986. Based on those technology, the matte chlorine leach electrowinning process (MCLE) has been developed as an alternation to the relatively old technology of matte electrorefining. The new process offers significant cost down and excellent quality of the product. In 1986, the feasibility of MCLE was confirmed by the test work using the integlated pilot plant. The innovation of the chlorine leach process has been undertaken by this work. The new refining process can be divided into three stages including chlorine leach stage, purification stage and electrowinning stage. More than 99 % of nickel was extracted in atmospheric chlorine leach. Although copper ion was used for electron carrier in the chlorine leach, the excess copper from the feed matte is bled off from the leach circuit by de copperizing electrolysis. The copper ion of the pregnant solution is fixed on nickel matte by the cementation reaction. The nickel matte containing copper is processed in the chlorine leach. In the purification circuit, cobalt, iron and other impurities were removed from the nickel chloride solution. The nickel chloride solution is then fed into the electrowinning cell. Based on the process established, the new plant with a capacity of 330 t/M electrolytic nickel was commissioned in order to obtain the engineering data for design of the full scale plant in 1989. The performance of the plant was fully satisfied and the new process demonstrated the potential application of modern process control.

Jan 1, 1992

By A Scott, I Onederra

Most iron ores occur in mine benches as complex mixtures of lithologies and ore types. This significantly complicates their characterisation for both blast design and fragmentation modelling. A great deal of technical and research effort has been applied to the development of models to predict fragmentation from rock blasting. A number of quite useful engineering models are currently available to blasting engineers and consultants, and more sophisticated approaches using mechanistic descriptions of rock breakage continue to be developed and applied by researchers and explosives companies.The engineering or empirical models that are in more general use within the industry, such as the Kuz-Ram model, require appropriate data if they are to generate useful fragmentation predictions. Some of these models have reached significant sophistication and have made very useful contributions to both routine blasting operations and the exploration of new blasting paradigms. However, these models struggle to adequately deal with rock that is as complex as iron ore. This paper reviews the characteristics of the most successful blast fragmentation models available to the industry and discusses approaches to the derivation of suitable rock mass properties to adequately describe blast fragmentation in a range of iron ores.CITATION:Scott, A and Onederra, I, 2015. Characterising the blasting properties of iron ore, in Proceedings Iron Ore 2015, pp 481–490 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By T R. Stacey

South Africa has a long history of rockbursts, some 100 years. During this time much research and many developments have taken place in the country to limit the occurrence of rockbursts, and to mitigate their effects. In this paper I shall present a personal view of what I consider to be important achievements, and contributions made. Some of these are: planning of stope layouts, and the use of strike barrier pillars; recognition of energy as a key factor, the use of the energy release rate ERR as a layout planning criterion, and development of MINSIM for calculation of ERR and stope planning; sequential grid stope layouts; use of backfill for stope support; and, development yielding support elements, and dynamic testing of stope and tunnel supports. The record shows the establishment of a rock engineering research powerhouse over a 40 to 50 year period and, unfortunately, the complete breakdown of this capability in the subsequent 10 years. CITATION:Stacey, T R, 2018. A personal review of South African rockburst research, experience and lessons learnt, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 5–16 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By C. M. Frost

Two Federal Bureau of Mines recycle hydrogenation experiments to prepare catalytic cracking feed stock were made at 3,000 pounds pressure with crude shale oil retorted from Green River (Colo.) shale in the gas-combustion retort. The hydrogenated product from the first experiment, made at 784° F., was used for investigating the effects of nitrogen content on catalytic cracking yields and for determining the quality of the catalytically cracked gasoline. Hydrogenated product containing 0.14 percent or more of nitrogen produced less gasoline when cracked in a CAT "A" unit than was obtained from East Texas light gas oil cracked at the same conditions; product containing 0.10 percent or less nitrogen produced a quantity of cracked gasoline equal to that obtained from the East Texas light gas oil. The catalytically cracked gasoline had research octane numbers calculated to be approximately 95 clear and 103 with 3 ml. of tetraethyl lead. The principal product from the second experiment, made at 828° F., was a low nitrogen content gas oil which was used for investigating the yields of cracked products obtained when it was catalytically cracked to different degrees of conversion. Yields of cracked products, when plotted as functions of conversion, were essentially the same, within the experimental range of the data, as published yields from catalytic cracking of East Texas heavy gas oil; however, yields from cracking the shale-oil product did not display the sensitivity to change of cracking temperature that has been found for East Texas gas oil.

Jan 1, 1960

By Won C. Park

Experiments showed changes in the mineral content of dolomitic oil shale at temperatures and exposure times which bracket conditions encountered during in situ retorting. Laboratory results correlate with cores from a spent in situ retort at Occidental's Logan Wash test site at Garfield County, Colorado. Dolomite, CaMg(CO3)2, decomposes rapidly to form periclase, MgO, calcite, CaCO3, and CO . Both calcite and periclase are intermediate products that can be stabilized by CO atmosphere at lower temperatures, while steam accelerates the formation 2 of silicates. The decarbonation of calcite appears to involve a direct reaction with both quartz and periclase in forming these silicates. Decarbonation preceeds the formation of akermanite, Ca2 MgSi 207, and diopside, CaMgSi 206, within several hours of heating and is followed by the nucleation of forsterite Mg2SiO4, and monticellite, CaMgSiO4. Under in situ retorting conditions, akermanite and diposide are the major minerals above 800°C. Equilibrium is not attained within 200-300 hours. In situ retorting temperatures above 800°C for extended periods of time should reduce potential ground water leaching by the formation of silicate minerals. These silicates are less soluble than free lime, magnesium or alkali oxides. There is a corresponding decrease in the natural pH of these silicates from approximately 12 down to 7.5 to 9:

Jan 1, 1981

By Larman J. Heath

Liquid incendiaries were burned within the interstices of several different types of sandstone cores to determine the technical feasibility of increasing sandstone permeability by this method. Fuel-oxidant mixtures were tested in 186 cores; six cores exploded when ignited. In virtually all instances, the explosion completely pulverized the sandstone cores. In addition n those cores damaged by explosions, 24 cores were fractured so severely that permeability tests were impossible. Although combustion gener¬ally increased the permeability, specific mixtures at given pressures were inconsistent in their ignition and burning behavior. Tests indicated that the heat of burning incendiaries significantly increased sandstone permeability. The improved permeability ratios were usually less than 2, but one was 10.3. Permeability alteration by other in situ methods was not as effective as that by flame propagation.

Jan 1, 1971