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By John Griffen

THE distinguishing principle of the Tromp process is the use of a medium in the bath which is not stable, i.e., the solids will settle and the density of the medium increases with depth. A medium of uniform density can most easily be effected by agitation or by means which increase the viscosity of the medium. Either of these works against the sharpness of separation of coal from its impurities. The Tromp process grinds the medium solids to relative coarseness, allows them to settle downward in the bath without hindrance, and introduces horizontal currents of medium at intermediate levels between top and bottom of the bath. This prevents any accumulation of particles denser than the upper layer of the medium from which the clean coal is conveyed away or an accumulation of particles lighter than the bottom layer or medium whence the refuse is removed. In a relatively shallow bath making a two-product separation, the intermediate horizontal currents sweep these intermediate gravity materials away to be discharged with the refuse removed by the conveyor. Such a system provides a number of advantages. The gravity of separation can be changed simply by changing the density of the medium without changing particle size of medium solids or other conditions, as would be necessary with a system requiring uniform or stable density throughout the bath. Some installations in Europe separate at 1.40 sp gr on one shift, producing a superclean coal, and on the next shift reclean refuse from dry cleaning units and effect a separation at 1.80 sp gr. Medium solids may be much coarser in size consist, which reduces the viscosity of the medium and promotes its fluidity and in turn the sharpness of separation. Coarser medium solids with a more rapid settling rate are much more easily recoverable from the dilute medium rinsed from the products. The Tromp process is not limited to the use of medium solids having magnetic properties. Instal-

Jan 1, 1953

By M. P. Dalton

THE problem at the Morning mill is to separate the galena, which contains a great percentage of the silver, from the sphalerite, making each into a commercial product. The ore as received from the nine is dumped into hopper-bottomed bins of 1200 tons capacity. These are divided into five sections, the first section being the regularly used section and the re-mainder used as a reserve bin. The ore is first passed through a 9 by 15-in. Blake jaw-crusher with an opening of 4 in. This allows a ham-mer head to pass through without damage. The crusher discharges to a conveyor that delivers the ore into a two-section punched-plate trommel screen with 1 ½ and 2-in. openings. The undersize is carried by means of conveyors to the mill bins. The oversize passes over a shaking feeder and through a spray or high-pressure water to a picking-belt, where waste and crude ore is hand-sorted. About 4 per cent of the ore by weight is picked out as waste, assaying about 0.6 per cent lead, and this is discarded over the dump. About 4 per cent of the ore by weight is removed as crude ore, assaying 10 oz. silver, 30 per cent lead, and S per cent zinc, and is shipped direct to the smelter. The remainder of the oversize from the picking-belt is con-veyed to a 4-ft. Symons cone crusher with 1-in. opening, which is interesting as a new introduction in this dis-trict. The machine consumes approximately 40 hp. and the pinion shaft travels 555 r.p.m. The horsepower is rather high, but the machine has an extraordinarily large capacity, and, due to the unique construction, there is no danger of tramp steel causing any damage, as in that case the discharge "opening" is automatically

Jan 7, 1927

By F. A. Harvey

DURING the last few years, there has been a constant tendency toward increasingly high temperatures in many lines of industry. The necessity for increased production of coke gave a 16-hr. coking period where we used to have 24 or even 30-hr. periods. Mechanical stokers have increased the temperatures in boiler furnaces. The use of a chain-grate stoker with coke-breeze fuel necessitates a low arch in the furnace and temperatures run much higher than firebrick were formerly called upon to stand. These higher temperatures have necessitated more rigid tests and the separation of even high-grade firebrick into separate classes. More severe tests mean higher temperatures and closer control, and this, in turn, means better pyrometer tubes. Platinum couples do not have a very long life when used at temperatures exceeding, say, 1200° C., but the proper selection of a high-grade brick to be used in a-boiler setting will save the cost of several couples; and with freight rates continually increasing it becomes increasingly important to know where brick may be bought, nearest the job, that will prove satisfactory. Couples that will stand continuous use at higher temperatures, of tungsten, molybdenum, or other metal, will doubtless be forthcoming as soon as the need becomes sufficiently urgent. There are on the market several tubes that are entirely satisfactory for temperatures up to 1300° C., if properly protected from heat shock. The Semet-Solvay Co. makes a practice, however, of testing silica and clay firebricks at 1450° C. for 72 hr., and so far we have been unable to find a tube that- is entirely satisfactory for this purpose. A graphic record of the temperature during the entire test is extremely desirable and hence we have been trying out anything that gave promise of success. Several years ago we were using insulating tubes, made purely for electrical work, of vitrified porcelain. These tubes stood up under any temperature we were able to reach and were apparently impervious to gases. When this stock gave out, due to mechanical breakage, we tried other insulation tubes only to have them melt down like glass. Marquardt Masse tubes were tried next under a statement from the distributors

Jan 9, 1919

By P. F. Richardson, J. L. Perisho, W. J. Roe

Handling and transport of coal during the winter months can be a severe problem. The inability to unload frozen coal from rail cars produces serious economic and logistic problems due to transportation delays, rail car shortages, and demurrage on the rail cars. One method of dealing with the problem of unloading frozen coal has been to spray freeze conditioning agents onto the coal before it is loaded into rail cars. Both water soluble and oil based formulations have been used as freeze conditioning agents. The water soluble treatments generally contain a polyhydroxy alcohol, such as ethylene glycol, or salts of alkaline earth metals, such as magnesium chloride and calcium chloride, as freeze point depressants. The oil based treatments consist principally of hydrocarbons, such as No. 2 oil or diesel fuel. The authors' tests have shown significant differences in the effectiveness of these freeze conditioning agents, depending on the particular coal substrate being treated. These differences correlate with the coal porosity and inherent moisture of the substrate. In general, the greater the porosity of the coal, the smaller the effect of the freeze conditioning agents. Coal porosity has a greater impact on water soluble freeze conditioning agents than oil based products. The authors investigated the pore structure of a variety of coals using mercury intrusion. Findings were related to the effectiveness of different freeze conditioning agents as measured by unconfined compression strength tests. In general, coals with a large number of very small pores (between 0.05 µm and 0.03 µm) do not respond as well to freeze conditioning chemicals.

Jan 1, 1986

By T. M. Williams

DURING the year just ended we have had three great fires in the mines in the Wilkes-Barre district. One at the Empire Colliery, one at the Prospect shaft, and the other at the Baltimore old mine. It is proposed in this paper to give a brief history of the fire at the Empire Colliery, and the methods employed in extinguishing it. The fire was first discovered breaking out in the air-stack, alongside what is known as the " Kidder Plane," about one o'clock on the morning of December 31st, 1873. Subsequently it was ascertained that the fire originated in the return airway somewhere near the steam boiler, located inside the mine, near the head of No. 5 slope. The coal from this slope was hoisted to the shaft gangway, at a point nearly four thousand feet distant from the foot of the shaft. As there were from four to five hundred mine cars hoisted per day from this slope the steam boilers were located at this place. The mines being of considerable extent required a large volume of pure air for ventilation, and no fan having been erected at this slope at the time, the heat from the boiler was made use of to assist ventilation, by conveying the return air from No. 5 slope into the large airway made from these boilers to the surface through the old "Kidder slope" to the stack where the fire was first discovered. The length of this slope or airway was about one thousand feet, with a sectional area of about sixty feet. The quantity of air passing through it must have been over sixty thousand cubic feet per minute

Jan 1, 1875

By W. B. Clarke

It is the purpose of this paper to discuss briefly some of the recent developmellts in connection with the use of electrical apparatus for the mining of coal. For several years electricity has been employed extensively for the distribution of power, primarily for the operation of mine-locomotives and chain coal-cutters, and secondarily for motors driving pumps, ventilating-fans, rope-haulage, conveyors, crushers, auger-drills, coke-oven larries, etc. The severe and peculiar conditions which attend the development and distribution of power for the operation of coalmining machinery constitute a field to which the electricmotor seems to be especially adapted. The underground use of steam-engines, to any great extent, is impracticable for obvious reasons. The much higher efficiency of the electrical system is a potent argument in its favor as compared with compressed air, which, under ordinary circumstances, should only be employed for the operation of rock-drills and coal" punchers." The conditions in many mines prohibit the under-cutting of coal with a chain-machine; and the compressed-air " puncher," with its very low efficiency, is extensively employed. There have been no recent important improvements in the design and construction of the chain-machine, although, of course, minor changes are continually being made. More time and attention are being paid now than ever before to the details of mining-machinery, with the idea of eliminating the weaknesses which have been developed, and especially of facilitating repairs and renewals. Electric mine-locomotives are very extensively employecl for the haulage of coal on the main entries and the branchheadings; but in the majority of coal-mines the cars are still

Jan 1, 1904

By John Henry Harden

IT appears that in the earlier days of anthracite coal mining, 1824-25, the Lehigh region mined 76 per cent. of all the coal sent to market. During the same period Wyoming sent 12 and 5 per cent. respectively, whilst the Schuylkill sent 11 and 18 per cent., the number of tons marketed being in those days very small indeed. In the year 1828 the Schuylkill region mined over one-half of all the coal sent to market, and continued to do so for thirty years (with the exception of the year 1831), until 1858 ; since that date the pro¬duction has declined very steadily in comparison with the other regions, until, in 1876, it was only 34 per cent. Wyoming, in the year 1820, was mining 40 per cent., but the production of all the regions was very small ; in six years it declined to 5 per cent., increased to 34 per cent. in 1831, declined to 10 per cent. in 1838. Since which time the increase has been gradual, until 1873-75 Wyoming produced over 50 per cent. of all the anthracite coal sent to market. In 1867 the production exceeded that of Schuylkill, and has continued to do so since that time. In the year 1876, during the existence of the " coal combination," Wyoming lost 9 per cent. ; during the same time Lehigh gained 7 and Schuylkill 2 per cent. over their relative production of the preceding year, the decrease of Wyoming being two and a half million tons, the increase of the Lehigh one million, the decrease of the Schuylkill nearly three-quarters of a million. The extraordinary production of the Lehigh region at a time of decreased demand and in opposition to an agreement with the other regions to limit the supply to the supposed demand was the cause of the disagreement which ultimately broke up the combination of the great coal-producing and carrying companies. The Lehigh region produced very steadily, from 1829 to 1854, an average of about 22 per cent. of the whole production. From 1854

Jan 1, 1877

By Raymond Ladoo

THE milling of talc, as is the case of many non-metallic minerals, until recently, has not received adequate technical consideration, for the talc industry has become of importance only within the last decade. At first, talc was used only in the massive form, for foot warmers, griddles, and so on, and milling methods were unnecessary. As the demand for ground talc increased, producers adopted the machinery used in the milling of flour; in fact, many talc mills were rebuilt flour mills. Improvement has been slow, but today several types of grinding and separating machinery are in use; many of them, however, are still inadequate and inefficient. To determine the best methods of milling talc, it is necessary to understand the essential properties a talc must possess to fit it for a particular use. For toilet purposes, whiteness, freedom from lime and grit, fineness of grain, and good "slip" are essential. As a paper filler or coating, the talc must be white, have a good slip, be free from grit and iron, uniform, and fine grained; freedom from lime is a disputed point. Fibrous talc is supposed to be superior to massive on account of the interlocking of grains in the paper, thus increasing its strength; this point, though, is in doubt. In general, talc for the paper industry need not be of as high quality or as fine grained as that used for toilet purposes. Talc is usually bought by sample, for which reason it is difficult to state the essential properties for use in paint, rubber, roofing, and so on. The adoption of standard screen tests and standard grades by producers is necessary before an accurate basis for manufacturing or selling standards can be established. Off-color tales might be utilized, as in Germany and-Austria, by the establishment of standard grades of colored tales.

Jan 1, 1921

By Heinrich Ries

In another place,* the writer has called attention to the modern methods of the laboratory investigation of clay, and it is desired here simply to discuss one branch of the subject, which, though of considerable importance, has heretofore received little attention in this country, viz., the rational analysis of clay. In order, however, the better to point out the bearings and advantages of this procedure, it is necessary to refer briefly to the ultimate analysis as well. The remarks in this paper refer only to the use of clay for the manufacture of clay-products. Pure clay or kaolin-f is extremely refractory, possesses little plasticity, and usually shrinks aud warps considerably in burning. Even the smallest proportion of impurities changes these properties, so that the kaolin exhibits variations in shrinkage, plasticity, tensile strength, fusibility, and often color when burned. The majority of nearly pure kaolins consist of kaolinite (A1,O2 2SiO,, 2H20), undecomposed feldspar, and quartz. The kaolinite generally forms the finest particles of the clay and is known as the clay-substance, while the rest of the clay-particles are collectively spoken of as sand. In the ordinary or ultimate analysis, the substances generally determined are silica, alumina, ferric oxide, lime, magnesia, alkalies and water. An analysis of this type simply regards the clay as a mixture of elements or oxides, but gives no clue as to the actual condition in which these substances exist, i.e., whether as silicates, oxides or carbonates, etc., a point which it is of the highest importance to know; for the individual components of the clay influence its properties not only according

Jan 1, 1899

By W. J. Locher

One important means of reducing steel consumption in grinding mills is not mentioned in S.G. Malghan's paper. It is simply to reduce the oxygen content in the mill and pulp. While oxygen dissolved in pulp is not readily reduced without additives, reduced aeration and reduced ventilation of grinding mills are often feasible. It is not necessary to completely eliminate the oxygen to achieve substantial benefits, since corrosion rates vary with oxygen content in a manner analogous to combustion rates as oxygen content increases. It is difficult to generate indisputable quantitative data on the relationship of oxygen reduction in a milling system to changes in consumption of grinding steel. Perhaps this accounts for the absence of technical papers on the effects of reducing oxygen content in grinding mills by reducing aeration of pulp and ventilation of grinding mills. One qualitative observation is that mills operating at a lower percent of critical speed will tend to have lower media consumption for similar fineness of grind without necessarily having an equivalent reduction in power consumption per ton of product. Reduced mill speed would also tend to reduce both ventilation of the mill and entrainment of air in the pulp. Larger grinding mills tend to be more media efficient because they operate at a greater ratio of charge volume to pulp surface area, which will tend to reduce the aeration per unit of pulp volume. The mechanical steps required to reduce aeration of grinding mill pulps depend on the configuration of the grinding circuit and related process. Reply by S.G. Malghan Mr. Locher stated that my paper did not mention the reduction of oxygen content of the pulp as a potential method of decreasing the steel consumption. I would like to bring to the attention of Mr. Locher that an indirect reference was made to the fact that pulp oxidation potential controls the corrosion wear of steel. Though dissolved oxygen is one of the factors that controls oxidation potential, additional discussion was deliberately avoided for the reasons mentioned by Mr. Locher. The most important reason being the difficulty of decreasing and controlling the oxygen concentration of the pulp in a commercial mill.

Jan 1, 1984

By Newell Hamilton

SOME years ago, in the manufacture of seamless tubing from an alloy steel containing 0.07 per cent maximum carbon, 18 per cent chromium and 8 per cent nickel, at the plant of The Babcock & Wilcox Tube Co., a peculiar type of piercing defect was noticed. This defect was definitely associated with certain heats of the alloy and was independent of any of the variables of mill operation and billet-heating condition. A thorough analysis of the defective material yielded but one clue to the reason for its abnormal behavior in piercing and that was its oxygen content as determined by the vacuum fusion method. The oxygen content of the defective 18-8 alloy was found to be from two to three times that of the material that had pierced satisfactorily, and this incited an active interest in the vacuum fusion method for the analysis of alloy steels. After a critical survey of the literature on this subject, and considerable experimentation, an apparatus and technique were evolved that gave a fairly rapid, simple and reliable method of analysis. Samples selected from six years of tube production of 18-8 and other corrosion-resistant alloys were analyzed by this method. This paper describes the procedure and gives a correlation of the oxygen, hydrogen and nitrogen contents of a number of alloy steel samples repre-sentative of good and bad tube-piercing quality.

Jan 1, 1934

By Robert W. Hunt

The first pump of this character, made by H. R. Worthington, and, so far as the writer is informed, the first and only one of this kind ever constructed, is now in daily use in the above-named works. The water-pressure necessary for the working of the hydraulic machinery of this plant had been supplied, up to the time of the building of this pump, by two Worthington Duplex High Pressure Pumps, having steam-cylinders of 20 inches diameter and 12-inch stroke, with water-plungers of 71/2 inches diameter; eight inlet and eight outlet valves of 24 inches diameter, and pumping into a 6-inch pipe. These pumps required a large amount of steam, and, in consequence of the various additions to their duty, their capacity became far short of the work required. In preference to putting in another engine of the same class, it was decided to accept Mr. Worthington's proposition to build the compound one under description, he guaranteeing that it should be equal to the demands of the works, and at the same time cause a saving of from 5 to 6 tons of coal per day from the amount required to run the two old pumps. The new engine has been in operation about one month, and so far has exceeded the most sanguine expectations. It consists of two high-pressure cylinders of 21 inches and two low-pressure ones of 363/8 inches diameter, by 36-inch stroke, with water-plungers of 961/2 inches diameter. There are two air-pumps of 20 inches diameter by 18-inch stroke; the condenser being 24 inches diameter by 60 inches high. Both cylinders are jacketed with wood and felt, and the low-pressure cylinder also with live steam. The high and low pressure steamcylinders are in line and immediately adjoining each other, while the inconveniences attending an internal stuffing-box are avoided by having two piston-rods for each of the low-pressure cylinders, running through stuffing-boxes on the outside of the smaller high-pressure ones. The steam-valves are very ingeniously designed balanced

By Harry M. Conger

It is a pleasure for me to keynote this first Western Regional Minerals and Coal Conference here in the Black Hills of South Dakota. It is pleasing for two main reasons. First, Homestake Mining Company has been associated with the Black Hills since 1875 when gold was discovered following Custer's trek through the Hills during 1874. Second, the future mineral development of the Black Hills will depend, to a great extent, on minerals and metals covered in this conference. The metals and minerals that are featured in this conference have unique similarities--and important differences--and therefore, will be of great interest to all who are involved in our industry in this area of the country. Precious metals have always been, and likely will always be, subject to political influence; they are only partially affected by the demands of our industrial economy. Energy minerals, while more directly affected by industrial stimulus, are also politically sensitive. In this regard, the need for a minerals policy affecting the energy sphere has been made very clear to us in the last five years. More importantly, the lack of a national policy and purpose relating to our total future energy needs has severely affected the overall economy and security of this country. Very briefly today, I would like to outline for you my thoughts on the future of these most important minerals. I will start by a discussion of precious metals, primarily my favorite precious metal, gold. A brief history of gold will be helpful in setting a perspective for forecasting its future although it is difficult to give a brief description of a metal that has been prized by man for over 6,000 years. Until recently, as you know, gold was held by the Federal government as a metal to be owned by the government only and

Jan 1, 1983

By Tadao Nagai, Masao Sato

Electrochemical measurements have been carried out in an auto- clave to investigate the electrochemistry of hydrogen precipitation of nickel from acetate buffered solution. After having previously obtained the rate equation for this reaction we have now made a concentrated effort to explain the rate equation electrochemically. A saturated NaC1-type Ag/AgC1 reference electrode has been improved so that it can be used in an autoclave. Polarization curves for the reaction, [H2=2H+ + 2e,] on nickel electrode were measured in solutions free from nickel ions at 185°C, and the parallel curves were obtained by changing PH2 and pH for normal and reverse reactions, respectively. Polarization curves in nickel solutions were complex, probably because the potential of hydrogen electrode is close to that of nickel and of the nickel surface altered during polarization. Then the nickel electrode potential and the reaction rate were measured simultaneously during pressure reduction at various hydrogen pressures and at various nickel concentrations. The reaction rates in terms of current density were plotted to obtain the local polarization curves for reactions Ni2+ + 2e ? Ni and H2 ?2H+ + 2e. The anodic and cathodic local polarization curves exhibit potential dependency. Therefore it is likely that the pres- sure reduction can be regarded as a coupled electrodes reaction.

Jan 1, 1973

By Carl H. Beal, E. D. Nolan

In February, 1918, the conclusion was published by Lewis and Beal "that wells of equal output on the average will produce equal amounts of oil in the future, regardless of the ages of the wells." This conclusion was based upon the study of data collected principally in Oklahoma and was not known at that time to be true for other oil fields. An abundance of statistical proof was later collected by the senior author of the present paper, which showed that the conclusion was undoubtedly well founded and that it applied to other fields as well. Accordingly, it was later restated2 as the "law of equal expectations" as follows: "If two wells under similar conditions produce equal amounts during any given year, the amounts they will produce thereafter, on the average, will be approximately equal, regardless of their relative ages." Although only scanty data from the California oil fields were available at the time this publication was prepared, sufficient information was analyzed upon which to base the insert on Fig. 80, which showed beyond a doubt that the law held at least for a part of the Midway oil field in California. Recently the authors have collected more complete data in California, and it is the purpose of this paper to explain the method used in demonstrating the truth of the law and, in addition, to give several methods by which curves constructed in accordance with this law can be used in a practical way with ease and accuracy. The Family Curve The law of equal expectations means that each individual of a group of wells producing under similar conditions will decline along approximately the same type of curve, the rapidity of decline varying with the output

Jan 1, 1921

By Wilhelm Rohn

When a metal solidifies, gas, initially present in solution, may be concentrated at the grain boundaries, leading to brittleness, or it may form solid compounds which, if localized at the grain boundaries, impair the properties. On the other hand, the solid compounds formed sometimes distribute themselves more or less uniformly, and hence may be relatively harmless. If metallic oxides are heated under a partial oxygen pressure less than that corresponding to the dissociation pressure of the oxide in solution in the melt, they will decompose and oxygen will tend to be eliminated from the melt. This paper presents data on the partial oxygen pressures of copper and nickel oxides over a wide range of temperatures; it also presents data regarding the amount and nature of the gases evolved in the vacuum melting of a 3500-kg. charge of nickel-chromium alloy and gives test values indicating the improvement in impact values ascribed to vacuum melting. The results of commercial experience with a 4-ton vacuum melting and casting furnace indicate that this method entails an increase in cost of about 10 cents per pound of ingot over orthodox practice, which may be justified for special products and may be lowered if hot metal is charged into the vacuum furnace. DISCUSSION (Howard Scott presiding) J. H. ScafF, New York, N. Y. (written discussion).—In the section of Dr. Rohn's paper describing the effect of melting -metals in vacuo, he says, "In this way plain copper, nickel and iron may be easily purified. For example, vacuum-melted copper does not contain any oxygen and for this reason it is never sensitive to hydrogen embrittlement." This statement is contrary to the results of our experiments at the Bell Telephone Laboratories on the effect of vacuum melting on the properties of copper. Several 150-gram samples of tough-pitch copper were melted in a vacuum of the order of 1 X 10-5 to 1 X 10-6 mm. Hg for 2 hr. Portions of the ingots obtained were swaged to 0.100 in., then drawn to wire 0.050 in. in diameter for physical and

Jan 1, 1933

By James Douglas

I had the good fortune to visit the Stockholm Exposition just before its close in October last, and to get a glimpse of the methods used in Sweden in making the wonderful steel and iron for which its furnaces are so famous. My time and opportunities for observation were limited, but some points which I noted may be worth bringing to the notice of the Institute. The Exposition itself was confined to the natural and artificial products of Scanclinavia, and therefore iron and steel held a very prominent place in it. There was a complete collection of the rocks and ores of the Peninsula made by the Geological Survey; and every iron-mine of note exhibited a glass model of its workings, as well as classified specimens, accompaniecl by thorough analyses of the ores. Another feature of interest was the display of models of the old mining-machinery, in the invention and introduction of which Sweden led the way, and of the old and new surveying-instruments and compasses devised for the exploration of the Swedish iron-ore bodies, all of which are more or less magnetic. The magnetometric collection and exhibit of methods of operation made by Prof. Nordestrijm were supremely instructive. The larger metallurgical works, such as those of the Kopparberg and Sandvik companies, exhibited their wares in separate pavilions, in which crude and manufactured objects were arranged most eflectively and tastefully; while the smaller companies erected in the Industrial Arts Building trophies, every one of which was an object of beauty. One was struck on all sides by the fine asthetic feeling exhibited in the ingenious installation of materials and objects not easily lending themselves to artistic treatment. Hammers, picks and drill-steel were grouped into mural designs which it was a delight to look at.

Jan 1, 1899

By K. C. Gilbart, Edgar Stansfield

When plants decay in a peat bog the woody parts form a brown pasty mass, or peat muck, largely soluble in alkalis. This brown matter has been termed "ulmin." The same material, but commonly black in color, is found in coal, and there is evidence of the similarity between the material forming the main bulk of the coal and the bulk of the more recently decayed material in peat bogs. The more recent or low-rank coals, such as lignite, little removed from the peat stage, contain notable percentages of alkali-soluble ulmins, but the percentage decreases with increased degree of coalification and is negligible in bituminous or higher rank coals. The determination of the alkali-soluble ulmins in any coal gives, therefore, an indication of its degree of coalification or rank. Coals which contain few or no ulmins soluble in alkalis do contain ulmins which can be rendered soluble by oxidation. The higher the rank of the coal, the more difficult it is to oxidize the insoluble ulmins and make them soluble. High-rank coals can be differentiated by oxidation tests on the insoluble ulmins; but low-rank coals can be characterized by both their soluble and insoluble ulmins. This paper deals with the determination and significance of the alkali-soluble ulmins present as such in the coal. The chemical nature and composition of ulmins are not discussed. Review of Literature The history of the study of ulmin is well given by Stopes and Wheeler.' The action of potash on coal has long been known, as Braconnot in 1819 distinguished between lignites and bituminous coals by stating that the former gave colored solutions with potash. Later the intensity of color was used to give a fuller differentiation. Hoffman2 distinguished between lignites and lignitic coals by the darker color given by the

Jan 1, 1932

By Frederick Laist

IT IS obviously impossible to design a copper smelting plant which could be considered, ideal under all conditions. For example, a plant properly designed to smelt the concentrates resulting from the treatment of porphyry ores by flotation would not be the kind of plant that one would design for the treatment of a coarse pyritous copper ore. The smelting of flotation or other fine concentrates is generally accomplished in a reverberatory plant, although occasionally the concentrates are sintered and then smelted in blast furnaces. On the other hand, coarse self-fluxing ores, whether pyritic or semi-pyritic, are generally smelted in a blast-furnace plant. Even this statement is only- approximately true, since the choice will be influenced by many factors; for example, the kind of fuel available (coal, oil or coke), the value of power (electric or steam), the uses to which waste steam may be put (heating, drying, etc.), the cost of refractories (silica and fire brick), the permanence and continuity of the ore supply and the relative first costs of the two types of plant (the reverberatory plant is generally more expensive to construct and to shut down), the contour of the site on which the plant is to be built (rugged, rolling or flat), the intelligence and character of the labor avail-able, and many other factors. From these remarks, it is evident that no copper smelter can be ideal for all conditions of ore and locality, and inasmuch as most of the copper now being pro-duced comes from fine or flotation concentrates and these are generally smelted in reverberatory furnaces, I shall confine my remarks to this type of smelt-ing plant.

Jan 5, 1923

We note with sincere regret the death of H. T. Chen,, who was killed by forest fire in the mountainous re-ion of Kokiu-Chang where he had been operating as Engineer in Chief of the Yunnan Tin Trading Co. Mr. Chen graduated in 1911 from the Department, of Mines, .University of California, being the first Chinese Government scholar in mining to attend that institution; and one of the first in America. He came of a distinguished family, many members of Which are in official life in Peking and in his native province of Hunan, all of whom are noted for their classical scholarship. He was himself a Hsiao-tsai or Bachelor of Arts, a coveted degree of the old literati class, Which he won under the Manchu regime when he was still a stripling. His mining work in Yunnan was carried on with only the most primitive facilities and in a distant province, but was, nevertheless, attended with great success and profit for his company. The region is infested with brigands and rebellious troops. who frequently turn marauders and prey upon the countryside, and Mr. Chen has had to go to the mines always with a large armed guard sometimes aggregating 150 men and some hundreds of miners, also armed. Two armed squads of men keep in touch with his base 'at Kokiu-Chang every day to get supplies and food, and it is feared that the brigands who have thus been prevented from plundering and mobbing his parties have started 'he fires to burn him out, with the disastrous result reported. Mr. Chen has thus given his life to his country in the attempt to win for modern China and Chinese civilization the raw materials of her new industrial life. He did so cheerfully and with full appreciation of the dangers that beset him, and China regards this as one of the most noble sacrifices of her young sons on the altar of patriotism. He is survived by a daughter of two years and by his widow who was also a graduate of the University of California and will be remembered by her classmates as Lucy Kong, 1912.

Jan 7, 1917