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This is the time of year tor the presidential address, and with the present incumbent engaged in the coal mining industry, it will therefore come as no surprise to you that the theme of my address this evening is concerned with coal.There are other reasons for this apart from my contact with the coal industry. At present, coal is supplying considerable overseas revenue at a time when the remainder of the mining market is in a somewhat depressed state. That times will change goes without saying, if history is to be believed.However, so far so good for coal. My first reaction when The Institute indicated its wish that I be president for 1976 was to become deeply conscious of the honour bestowed on me.On consideration, I realized that very few past presidents have been intimately connected with the coal mining industry to the extent of indulging in it for lengthy periods as a full time occupation or, conversely, a part time interest for a long time. It also appears that not one had started their career in the industry. In my case, 'also, there were 8 very interesting years ,as a gold miner and metallurgist before commencing in coal.It therefore seemed appropriate to endeavour to discover ,why this should be so, as coal mining is now a very important part of a very important industry. What were the reasons why the industry took so long to emerge when there were ample reserves of easily accessible coal?Frankie and Johnnie in their bar room epic of the depression years concluded, and I paraphrase, that "their story held no moral, their story told no tale". If my story has such a message, it could perhapsbe construed as reinforcing the oft-repeated dictums, true or false, that "history repeats itself" or "man never learns".Coal mining is by far our oldest major Australian industry except for agriculture. Its history is almost as old as that of settlement:For various reasons, there has been a glamour associated with metal mining ventures which prob...

Jan 1, 1976

By K. T. Aye

An investigation into the leaching of chalcocite and covellite in cyanide solutions at concentrations typically encountered daring gold cyanidation has been conducted. The results indicate that, for both minerals, the extent of leaching is greater under anoxic conditions, but is still incomplete even in the presence of free cyanide ions, with undissolved copper solids remaining in equilibrium with solution species. The speciation of the sulfur and cyanide reaction products in solution are interpreted in terms of the fast formation of a copper(I)- cyanide complexes in solution and a sulfur-rich copper(I) polysulfide solid phase, which then reacts more slowly to produce thiocyanate ions.

Jan 1, 2011

By K. L. Komarek

Based on theoretical and experimental evidence a discussion follows of the behavior of phosphorus -bearing iron ores in the R-N Direct Reduction Process and suggestions are made of methods of reducing the amount of phosphorus in the metallic end product. In ferrous metallurgy a direct reduction process is one in which iron ores are reduced to metallic iron with gaseous or solid reductants without the appearance of a liquid phase. A number of attractive features have induced several companies and government agencies to invest in the development of direct reduction processes. A summary of all direct reduction processes up to 1954 has been given by Barrett,' and Wiberg,2 and Willems3 have reviewed the most recent developments in this rapidly expanding field. Many difficulties have been encountered in direct reduction processes and the nature of these difficulties has varied from process to process. One problem common to almost all of them is the removal of phosphorus which is one of the reasons for the rather pessimistic outlook given by some government publications4'5 to direct reduction processes. In this paper an attempt is made to give a theoretical explanation of the variations in phosphorus removal observed in the R-NY Direct Reduction Process. However, many conclusions are general enough to be applicable to other processes. Most iron ores treated by the R-N process yield products lower in phosphorus than the original ore. A qualitative account of the factors has been given by Stewart, Reed, and Herasymenkoe but the erratic removal of phosphorus from some ores and the general importance of this problem make a more careful analysis of the theoretical aspects desirable. In the R-N process mixed ore or balled fines, ex-

Jan 1, 1963

By Albert Ledoux

SEVERAL years ago my firm was representing the Mt. Lyell Co. of Australia, which was shipping its blister copper to a refining works in the United States. After the contract had been running for many months, the superintendent of these works discovered that if water was poured upon the surface of the bars much of it would disappear into the interior through blow holes. -Some experiments made by him showed that this could be a considerable amount, so that copper which had been rained on before it was weighed, although the surface appeared dry, nevertheless would contain water. It had frequently occurred in our experience-as samp-lers that the drillings from a lot taken by boring would come out quite wet, and in some cases, indeed, water would drip into the sample pan placed below the bars, due to the fact that the drill had penetrated a cavity or cavities containing water, which presumably got into the cavities at the time the copper was water-cooled after casting, there being, perhaps, no outlet to the surface. So far as I know, until this discovery at the refining works, no. one had thought that rain could penetrate into the interior of blister copper; at least in any quantity sufficient to be considered.

Jan 10, 1922

By Lloyd R. Jackson

IN the past 15 years there has been a great deal of interest in the fundamentals of plastic flow and rupture in metals and a number of papers have presented substantial advances toward a fundamental insight into the mechanism of these two processes. This paper is an appraisal of the present position with respect to the following: I. The relative importance of shear and hydrostatic stresses in controlling the plastic flow of metals. 2. The relative importance of shear and hydrostatic stresses in determining the amount of flow before rupture in metals. 3. The use of generalid strains in determining the effect of plastic flow on the work-hardening of metals. FUNDAMENTALS INVOLVED IN PLASTIC FLOW In attempting to devise a quantitative description of plastic flow in metals, it has been customary to assume that metals are homogeneous and isotropic. The fact that neither of these assumptions is correct complicates the experimental appraisal of relations developed. Never- the less, as will be shown, metals are close enough to being isotropic and homogeneous so that considerable insight into the mechanism of plastic flow can be obtained. The assumptions of .isotropy and homogeneity allow both the elastic and plastic behavior of metals to be described in terms of 12 variables-six being stress variables, and six being strain variables. ) From this viewpoint, it should be possible to represent the stress-strain relations in the plastic range for metals by a surface in 12 dimensions. One boundary of this surface would be the surface of transition from elastic to plastic behavior; the other would be the surface of rupture. These two surfaces would be joined by the surface of plastic flow. The shape of this composite surface would depend on the test temperature and speed of straining. This paper is concerned only with results obtained at constant temperature and constant speed of straining. While such a representation is conceivable, the demonstration of such a surface would present almost insurmountable obstacles. The most fruitful simplification of this concept has been the recognition that the behavior of metals in the plastic region is primarily a result of shear stresses and strains. Based on this viewpoint, it is possible to utilize stress and strain invariants that are independent of hydrostatic components to define an effective stress and strain. In effect, this amounts to reducing the task of representing stresses and strains in 12 dimensions to one of representation in two dimensions. The two invariants (one for stresses . and one for strains) that have received most attention are the following: [ ]

Jan 1, 1946

By Treglown N

In any mining operation the curtailment of rising operating costs is of prime concern to management.One area of activity where costs are often disguised is that of longhole secondary breakage.This paper outlines sane operational techniques that have been considered and tested, resulting in improved fragmentation fran longhole stope blasts at New Broken Hill Consolidated Limited mine, Broken Hill, NSW.

Jan 1, 1985

By Gole MJ

The Goodyear nickel prospect is located 45 km southeast of Kalgoorlie (31.04¦S, 121.80¦E) near the eastern boundary of Hampton Area - East Location 45 (Figure 1). Nickel mineralisation was discovered on the Goodyear prospect in March 1996 when a reverse circulation drillhole (GYC5), initially drilled in December 1995, was deepened to meet a minimum footwall penetration requirement of 20 in that had been set for the drill program. Approximately 3 in of sulphides averaging 4.9 per cent nickel was intersected from 296 metres down-hole, this being within 2 in of the first end-of-hole. Hole GYC5 was part of an eight hole drilling program undertaken by Titan Resources in late-1995. This program was designed to test whether nickel mineralisation in the Dunlop prospect, discovered by the Western Mining Corporation - BHP Camylia Joint Venture immediately east of the East Location 45 boundary, continued across the tenement boundary. The area targeted by the initial drill program had been explored by Western Mining Corporation in the mid-1980s using extensive surface sampling and a drilling program that included 17 RAB and percussion drillholes. None of these holes intersected nickel Mineralisation.\

Jan 1, 1996

By Jerry G. Rose, Robert C. Howell

This paper addresses a process by which both the disposal and utilization of preparation plant coal refuse can be simultaneously accomplished with an attendant benefit of significantly increasing the percentage of extractable coal. A laboratory study is described in which coal refuse was successfully utilized as an aggregate in low cost concrete (coal-crete) mixes under simulated mine environments. Coal-crete specimens with compressive strengths of 14 000 kPa (2000 psi) were consistently produced. A construction sequence and mining plans are offered for placing the low-cost coal-crete pillars in accessible areas in room and-pillar mines so that a substantial portion of the remaining coal pillars could be extracted. The method could be applicable in areas where mining procedures do not permit pillar extraction became of possible surface subsidence, roof problems, or other conditions. Possible structural difficulties with the coal- crete pillar support system are discussed. Using a discounted cash flow analysis, the economic feasibility of mining with the coal-crete pillar system is investigated. The cost of the system is compared to the cost of a mining system which would have less coal recovery. The analysis indicates that although at higher coal selling prices the coal-crete mining system may yield an acceptable rate of return, the alternative of leaving the coal pillars is more attractive at the present time.

Jan 3, 1979

By Allan J. Clark

It is nearly three years since the metallurgy of the Homestake ore was discussed with considerable thoroughness, in a paper1 read before the Institution of .Mining and Metallurgy. Certain changes have been made in this period which are perhaps of sufficient interest to justify a brief description, and it is chiefly with such details and miscellanies that this paper will deal. In the circumstances, a certain amount of repetition is inevitable, but matter treated of in the former paper will be referred to here only when it is necessary for the sake of coherency. For full descriptions of equipment and technique, the former paper should be consulted. The mineralized slates and schists which constitute the ore vary considerably in composition, but the unoxidized ore, perhaps constituting the major part of the reserves, contains either chlorite or hornblende (cummingtonite), with quartz, carbonates of lime, magnesia and iron, and arsenopyrite, pyrite, and pyrrhotite. Ferrous minerals predominate, and this fact has been an important factor in determining the metallurgical treatment. With one or two exceptions the minerals noted are of relatively high specific gravity, and the ore as a whole is exceptionally heavy, many determinations giving an average specific gravity of 3.00. This high specific gravity presents one decided advantage, when the cost of treatment is compared with operations elsewhere, in that the ton, almost universally the basic unit, represents a volume probably less by 10 per cent. than that of many gold ores. On the other hand, this high gravity renders more difficult the discharge of pulp from mortars, its distribution on amalgam tables, and its transportation in launders. In the same way, as attesting the usual balance of such variations of different ores, it may be noted that the needle-like fibers of hornblende (cummingtonite), interlacing throughout the mass, render the ore more difficult to crush than would be anticipated, but on the other hand assist

Jan 1, 1916

By Norman Miskelly

Substantial progress has been made over the last ten years in the development of uniform national and international standards covering the definition, estimation and public reporting of mineral resources and mineral reserves. Agreement between the major participating countries has been reached, which include the requirement that a Competent Person prepares and approves publication of mineral resources and reserves. Most national regulatory organizations have accepted the new standards and have included them in the rules that must be followed by mining companies operating under their jurisdiction. These developments are the result of a concerted effort on the part of professional societies, national regulatory agencies, international organizations, and many dedicated individuals. The historical development of these standards is summarized in this paper. Accepted definitions of mineral resources and mineral reserves are discussed, as well as the definition and role of the Competent Person. Additional effort is needed before the international standards are fully understood, accepted and followed by mining companies, regulatory agencies, the investment community and the general public. Steps being taken toward development of a Mineral Reserves International Reporting Code Template (International Template) that will be available for all countries to use in deriving their specific country reporting codes, are outlined

Jan 1, 2003

By Michael D. Fenton

Detailed comprehensive assessment of the performance of Afghanistan's mineral industry during 1987 is virtually impossible, owing to the paucity of reliable published information. It was evident, however, that the level of civil disorder, now in its eighth year since the arrival of significant numbers of Soviet troops, was in actuality little removed from open civil war. Insurgents controlled substantial areas of the country and imperiled any industrial activity in many places. Assistance programs by the U.S.S.R. and other Eastern European nations were directed at developing the country's meager mineral industry, but the economy was generally viewed as chaotic. The inflation rate was somewhere between 20% and 30%; major food shortages contributed to the discontent of the population, and numerous villages were devastated by Soviet and Afghan Government campaigns to destroy the insurgents and cut their supply routes. Moreover, proposals by the Soviets and the Kabul Government aimed at reducing tensions with the rebels and scaling down the warfare seemingly were taken by the opposition as signs of weakening by the Soviet-backed Government, and rather than reducing aggressions, seemed to heighten insurrectionist activities. Efforts to entice the substantial number of Afghans who have fled to nearby areas of Pakistan and Iran to return to their country seemingly were failures, and indications near yearend that the Soviet Union might soon begin withdrawal of its occupation force of nearly 120,000 did little if any to reduce disorder.

Jan 1, 1989

By N Javati, G D. Carman, D Kikiha, B Likia, K Dala, J McPhie, R Johnstone, D R. Cooke, J L. Blackwell

The 40 Moz Ladolam gold deposit on Lihir Island, Papua New Guinea is the worldÆs largest, low-sulfidation, epithermal gold deposit, in terms of contained gold. The deposit has average grades of 2.42 g/t Au (LGL Resources Reserves Update, 2008) and gold is hosted primarily in refractory pyrite. Lihir Island is part of the 150 km long, Tabar-Lihir-Tanga-Feni, alkalic, volcanic island chain located in the New Ireland basin. Five volcanic blocks comprise Lihir; Plio-Pliestocene Huniho, Kinami and Luise volcanic edifices are built on top of remnant Pleistocene Wurtol Wedge and Londolovit Block (Wallace et al, 1983). The Ladolam gold deposit is located in the central portion of the dissected Luise volcanic edifice and is composed of four main orebodies: 1. Minifie, 2. Lienetz, 3. Coastal, and 4. Kapit. An active geothermal system is overprinted on the ore deposit, localised along north-trending lineaments, and is expressed as hot mud pools and fumaroles. The focus of open pit mapping and drill core logging, as part of ongoing PhD research, has been in the Minifie and Lienetz orebodies. The deposit geology is grouped into four main phases: 1. volcano-sedimentary host rocks, 2. porphyry-style biotite alteration and related hydrothermal breccias and veins, 3. epithermal-style breccias and veins, and 4. modern geothermal alteration. Gold is associated with epithermal-style alteration and mineralisation. Ongoing observations of the Minifie and Lienetz orebodies are highlighting differences in the geology and paragenetic histories. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By L. Shoke

The aim of this study was to develop an in-house tensile testing procedure that would yield accurate and reproducible parameters as input material properties into computational models for numerical simulations of the mechanical behaviour of TM380 mild steel. To achieve this objective, we reviewed the ISO 6892:2009 tensile testing standard along with reported good practice guidelines. Tensile tests were conducted on a dog-bone shaped TM380 mild steel specimen with strain gauges attached on either side, to monitor alignment and measure strain, using three different types of tensile testing machines. Parameters quantified included yield stress, ultimate tensile strength, and modulus of elasticity. The values of these parameters were found to be in agreement with the values supplied by the manufacturer's specification and showed minimal variations between laboratories. Thus it can be concluded that the tensile test procedure used resulted in accurate and reproducible results. The strain values calculated as per standard were in disagreement with those determined from extensometer and strain gauges and resulted in lower elastic modulus values. This confirms that the current testing procedures require the use of long-range strain gauges or extensometer to determine the strain. A chemical analysis was conducted to verify the specification by the manufacturer. The specimen was found to be fairly homogeneous with minor sulphide inclusions. The micrographs reveal a pearlite and ferrite structure typical of mild steel, and the fractographs show a dimpled surface typical of ductile fracture, which is an attribute of mild steel.

Jan 1, 2013

Blasting, particularly bench blasting, uses finite length cylinders of explosive close to two free faces. The rock to be blasted is usually intersected by a complex 3-D system of joints. To fully simulate a blast, a 3-D dynamic model is required. It is shown that the static stress distribution around a long cylinder can be reproduced by superposing the static stress distribution of a suitable chain of spheres. Thus, the dynamic results for individual spheres given by Favreau (1969) can now be substituted for the static results to give a dynamic model of the stress distribution around a long cylinder. Comparison of measured and computed waveforms show that the measured waveforms are much more attenuated and dispersed than expected. The consequences for explosive evaluation and design are Discussed.

Jan 1, 1990

HAVING previously shown you how ores are found and mined, and also how they are prepared and disposed for smelting, and then how the blast furnaces and other furnaces are made for purging their earthiness, all this would be as nothing if I did not proceed to show you the method of smelting them. Therefore, in the present chapter I wish to show you how you must proceed in this very important operation, telling you all I have seen and also how much work with this kind of blast furnace I have done or directed. For this reason I tell you first to take by weight or measure the quantity of ore that you wish to smelt and, particularly if it is a kind that contains silver, break it into small pieces about the size of [52v] beans. If the ore had previously needed evaporation by fire or cleaning by washing, you will have had this done well and have had it properly prepared by a master sorter or others. A layer of this is arranged on a bed of planks, bricks, or flat stones in front of the blast furnace and its companion is placed on top, then a quarter part of galena or a third if you can obtain it. Then an equal part of crushed iron slag or slag from the same or different ore is added. These materials are spread in layers one above the other. When the blast furnace has been constructed as taught above, correct in all its parts, and is full of well-kindled burning charcoal, then fill it up with charcoal and admit water to the bellows machine. When you see that it is well kindled again from this wind and that the flames begin to come out forcefully on top, work it down with a little rake and fill it up again. Then the pannier is filled with new charcoal, the blast furnace heaped full, and another basketful of the said composition of ore is also put on top. Proceed in this way, continually adding charcoal and ore as long as you have any, or as long as you wish to keep up the work, maintaining the blast furnace always full, or continuing in this way until the bottom of the blast furnace is filled with melted materials. Decide this by judgment, or by seeing through the mouth of the tuyère where the wind of the bellows enters that they are level with this. Then with an iron tool open the hole that was left as an outlet in front of the blast furnace and allow all the metal with its slag to run out. These two things, flowing through the chan-

Jan 1, 1942

By A. Kapoor

Gold mill effluents contain toxic pollutants such as cyanide (CN), thiocyanate (CNS), ammonia (NH4-N), and a variety of toxic metals. Various practical and economical technologies are in use for the removal of CN and toxic metals from gold mill effluents, however, the removal of CNS and NH4-N is challenging. The presence of CNS and NH4-N may make effluents toxic to aquatic life. The new Canadian Metal Mining Effluent Regulations will require mine effluents to be nontoxic. As a result, there is a need to develop practical and economical technology for CNS and NH4-N removal. The Mine Effluents Program in the Environment Group is presently evaluating biotechnology processes for the removal of CNS and NH4-N from gold mill effluents. The processes being evaluated are attached growth systems such as a Rotating Biological Contactor (RBC) and completely mixed suspended growth systems such as a Sequencing Batch Reactor (SBR) operating in a batch mode. The research to date at MMSL has shown that the RBC is very effective in removing CNS and NH4-N from simulated effluents. The NH4-N removal project showed that the RBC is capable of removing 0.8 g NH4-N/m2 of RBC disk area per day at an average temperature of 4.5 oC and hydraulic loading rate of 0.02 m3/m2/d. The RBC was also found to be very effective in removing CNS (feed = 200 mg/L and effluent < 1 mg/L) at 8 oC and a hydraulic loading rate of 0.02 m3/m2/d. The SBR was effective in removing CNS and NH4-N (generated from CNS degradation) at SBR operating conditions of two-12 h treatment cycles and a temperature of 12 oC. The end product of CNS and NH4-N oxidation was NO3-N, which is relatively non-toxic.

Nov 1, 2002

The Directional Drill Monitor (DDM) is an advanced instrument for real time in hole surveying. It was developed by Du Pont (Australia) to suit Australian gassy coal mining conditions. The instrument consists of three units: i. Down hole transmitter ii. Acoustic transducer iii. Data receiver processor unit (i.e. up hole unit). This paper describes the function of each unit in detail and highlights the importance of the DDM in long hole drilling efficiency. Surveying is carried out independent of hole depth. Each survey takes 2-3 minutes to complete, the frequency of surveying to control borehole trajectory is determined by the accuracy required for a particular hole.

Jan 1, 1992

The standard charge weight scaling laws imply that only one particular delay (that possessing the maximum instantaneous charge) contributes to the ppv. However, the present analysis clearly demonstrates that a varying number of blastholes contributes to the ppv. This number also increases with distance, x, between the blast source and the detector, and is caused by waveform broadening due to attenuation. Thus the operative charge weight, itself, is also a function of the distance, and so makes the standard charge weight laws difficult to implement. If the delay time scatter is neglected, then, under certain conditions, relatively simple expressions can be derived for the ppv magnification, FN, as a function of the number, N, of blastholes. When the influence of delay scatter and random fluctuations in each blasthole vibration is included using Monte Carlo simulations, then, to a first approximation, the condition FN=KNx applies, where KN is a constant dependent upon N. Unfortunately, however, for any particular blast this condition cannot be distinguished from the standard charge weight scaling law. The dependence of ppv on N would only be apparent if blasts of differing N were to be compared in an otherwise identical environment. Since this situation is very difficult (if not impossible) to realise, then the influence due to N, although significant, goes largely undetected. Another problem associated with standard charge weight scaling laws is the difficulty of accurately assessing the appropriate charge weight, even if attenuation broadening is neglected. For example, if a number of blastholes are very close, then they experience a vibration interaction which is non-linear. However, if the same blastholes were to be widely spaced, then the separate vibration signatures add linearly. The standard charge weight scaling law fails to distinguish between such linear and non-linear regimes. Unfortunately, in many production blasts, both regimes exist throughout various portions of the blast spatial pattern and so makes it difficult to determine the operative charge weight. The solution to the combined influence of waveform broadening and linear/non-linear interactions will obviously require substantial future research. A possible solution may be found in the use of numerical dynamic codes.

Jan 1, 1990

By B. M. Larsen

A discussion based on three commercial furnace tests and electrical analogue calculations is presented. It shows that while regenerator efficiency is mainly dependent on loading or relative amount of heat exchange surface plus the heat transfer coefficients as effected by flow velocity, the actual air preheat temperature can be high or low, largely independent of regenerator efficiency, mainly due to the diluting or unbalancing effects of cold air leakage into various parts of the furnace system. THERE are many signs of a renewal of interest in the heat regeneration aspect of the open hearth process, among them being the recent paper by Marsh,&apos; the introduction of auxiliary checkers in the stacks of the Isley furnace design, and a number of recent installations of two-pass checkers in new and old furnaces. However, there are also signs of yielding to the usual temptation of oversimplifying a problem. Faced with the job of obtaining better draft on a furnace, for example, a good designer always recognizes that focusing attention on some one factor, such as height of the stack or capacity of the exhaust fan, does not make his problem any easier; rather he must look at the whole system, including such items as valve resistances, bends in the flues, and flow resistance in the waste heat boiler; then he must make his design in relation to the available draft so as to avoid any serious bottleneck in the system. Yet this example is really much simpler than the problem of air preheating, and again, the latter problem is not really made easier by concentrating on air temperature in uptakes and on the more obvious methods for making this air as hot as possible. Also to be considered are such things as the total amount of air needed theoretically for complete combustion at any selected fuel rate, together with that needed for oxygen absorbed into the bath and for burning the combustible gases given out from the bath, plus some excess air. Furthermore, how does this total air requirement relate to the regenerator efficiency at various loadings? How much of the total air equivalent in stack gases will come from preheated air passed through the whole length of the incoming regenerator and how much from air leakage into various zones of the whole furnace system? Does the effect of leakage air differ depending on whether it leaks into the ingoing regenerator, the furnace above floor level, the outgoing regenerator, or the stack zone? Over a number of years we have in this Laboratory experimented with methods for measuring hot gas temperatures; we have measured, approximately, the efficiency of a few regenerators on commercial furnaces and we have developed an electrical analogue&apos; for calculations of regenerator efficiency. The whole problem is too complex to cover in one paper even with a more complete background of data than we possess, but we can attempt here to clarify certain aspects in a general way, hoping to assist specific plant studies on individual furnaces. Some of our earlier experience has been incorporated into chaps. 4, 19, 20, and 21 in the book "Basic Open Hearth Steelmaking,"" and on the assumption that this text is available to most readers, this discussion has been shortened by references to that book. The most recent design of a flowing-gas thermocouple which we are now using for measurement

Jan 1, 1955

By John J. McKetta, Donald L. Katz

Recent experimental data on the methane-n-butane-water system have been combined with data in literature to present: (I) the water-vapor content of natural gases, (2) the solubility of water in hydrocarbon liquids, and (3) the solubility of natural gases in water. Since water is present in petroleum reservoirs, experimental data regarding the behavior of water in hydrocarbon-water systems is of increasing engineering importance. A survey of literature (Table I) shows that data of these types are fragmen-tary at temperatures above the hydrate region. Experimental data taken from the authors&apos; recent investigation of the meth-ape-n-butane-water system are presented.17

Jan 1, 1947