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By Richard L. Coleman

Metallurgical testwork to develop a flowsheet is described, beginning with background information required right through to a final process flowsheet. Both laboratory and pilot plant testing are reviewed with emphasis on the former.

Jan 1, 1978

Freeman, the English historian, said that he had learned from Macaulay "never to be afraid of using the same word or name over and over again if by that means anything could be added to clearness or force. Macaulay never goes. on, like some writers, talking about ' the former ' and 'the latter ', 'he ', 'she ', 'it), and 'they’, through clause after clause, while his reader has to look back to see which of several persons it is that is so darkly referred to". He might have learned also from Macaulay that a preposition makes a feeble ending for a serious statement. How often do you hear 'the former' and 'the latter' in conversation? Good conversation is a guide not to be disdained. When you must use 'the latter ', do not confuse it with 'the last '. Cheap labor, cheap fuel, and cheap transport are essential, the latter [last] being particularly important in base-metal mining. The apparatus may be used to determine such gases as hydrogen sulphide, chlorine, oxides of nitrogen and some others, as well as sulphur dioxide. In the case of the latter two, etc. The two last mentioned are "sulphur dioxide" and "some others". He should have stated which two, and he should have avoided that wretched phrase "in the case of ". Pinning may be partly prevented by use of chalk, oil, or turpentine. The latter [last] is beat. "Partly prevented" is a poor phrase. 'Prevented' is a word that does not lend itself readily to modification. He means ' checked ' or 'corrected '. These steps are necessary to produce the gas, crude oil, and ammonia, the latter [last] of which is in solution in the water obtained along with the oil.

Jan 1, 1931

By Reno H. Sales

The present-day application of geological knowledge to mine operations owes much to Survey activities. Early publications covering developed deposits at Comstock and Eureka in Nevada, and Leadville in Colorado, aroused great interest in mine geology among mine owners and operators. In later years personal contacts between Survey geologists, notably Lindgren, Spurr, Emmons, Weed, and Ransome, to name only a few, and mine managers, mine superintendents and mine foremen, brought directly home the importance of geological mapping and study in connection with mine operations. However, the Survey had recognized from the beginning that it was not practicable, either from the viewpoint of cost or policy, to supply direct help to the miner. The situation was met by many large mining companies through the organization of geological departments to deal with problems of geology which concerned not alone the every-day mine operation but also the life expectancy of the ore deposit. The mine owner therefore looked to the mine geologist to apply the "laws of ore deposition" in estimating the future of his mine. The examination of outside properties also became a duty of the company geologist where replacements were needed or where expansion of operations was contemplated. And finally, out of this situation there developed the independent consulting geologist, specializing in geological examinations of prospects, mines, and mining districts, whose duties included the highly important but often difficult task of appraising ore reserves and ore possibilities. Thus, while it may be considered by many that the work of the mine geologist overlaps that of the Survey geologist, their respective fields of endeavor are not in conflict. The appearance of the mine geologist has lessened in no manner the need of intensive field and research work by the Geological Survey and related organizations.

Jan 1, 1935

By Reno H. Sales

The present-day application of geological knowledge to mine operations owes much to Survey activities. Early publications covering developed deposits at Comstock and Eureka in Nevada, and Leadville in Colorado, aroused great interest in mine geology among mine owners and operators. In later years personal contacts between Survey geologists, notably Lindgren, Spurr, Emmons, Weed, and Ransome, to name only a few, and mine managers, mine superintendents and mine foremen, brought directly home the importance of geological mapping and study in connection with mine operations. However, the Survey had recognized from the beginning that it was not practicable, either from the viewpoint of cost or policy, to supply direct help to the miner. The situation was met by many large mining companies through the organization of geological departments to deal with problems of geology which concerned not alone the every-day mine operation but also the life expectancy of the ore deposit. The mine owner therefore looked to the mine geologist to apply the "laws of ore deposition" in estimating the future of his mine. The examination of outside properties also became a duty of the company geologist where replacements were needed or where expansion of operations was contemplated. And finally, out of this situation there developed the independent consulting geologist, specializing in geological examinations of prospects, mines, and mining districts, whose duties included the highly important but often difficult task of appraising ore reserves and ore possibilities. Thus, while it may be considered by many that the work of the mine geologist overlaps that of the Survey geologist, their respective fields of endeavor are not in conflict. The appearance of the mine geologist has lessened in no manner the need of intensive field and research work by the Geological Survey and related organizations.

Jan 1, 1935

By A. H. Hand

When considering the question of future demand for crude petroleum in California, one must first decide whether it is to be approached in the light of the definition of "demand" when used in economics; i.e., "The quantity of any commodity required or sought in the market," or in the light of markets developed to dispose of total supply. Therefore, is the California demand of future years to be predicated on a continuation of supplying markets developed following the surplus production commencing in 1922, or predicated on supplying what would be termed economic markets ? If the latter, what are economic markets ? Obviously, the Pacific Coast States and Canada, Alaska, Hawaii and probably the Pacific side of Central and South America, can be considered as normal markets for California petroleum products. While there have been small quantities of gasoline shipped into the PacSc Coast from East Texas, transportation costs, plus import taxes in the case of foreign oil, are a sufficient barrier to justify considering that these markets will be retained. But how about our participation in Atlantic and Pacific foreign and intercoastal markets? During the five years preceding 1931 California shipped substantial quantities of gasoline to the United Kingdom and to France, Germany and Italy. During recent years our business in European markets has been restricted to occasional shipments of gasoline and Kettleman crude. This loss of business is occasioned by the development of production in the Mid-Continent, principally East Texas, and in Iraq, Rumania, Venezuela and other closer producing areas, which makes it impossible at the prevailing crude-oil prices for California to be competitive in supplying any substantial portion of these markets. It is therefore apparent that under a stabilized price structure that will return the California producer a reasonable price for his oil, future Atlantic foreign -business will be restricted to occasional spot cargo sales. As to Pacific foreign shipments which, in addition to Central and South America, consist principally of shipments to Japan, China, Australia and New Zealand: A considerable portion of the business we had with Australia and New Zealand until four or five years ago is now being

Jan 1, 1937

By C. W. Hill

FLUXES, in general, may be classified according to their use as soldering, foundry or casting, and metallurgical and the chemistry of their action follows quite closely this division. The term foundry or casting fluxes, as used here, refers to the substances added to molten metals, preparatory to casting into molds or ingots, with the object of removing small amounts of impurities that have been introduced in handling or melting the metal, which was placed in a fair state of purity by the previous refining or metallurgical processes. The sources of these impurities are the oxide coating on the surface of the ingots, material extracted or mechanically removed from the crucible or furnace wall, and those formed by the reaction of the molten metal with the heating gases or furnace atmosphere. As commonly used, the term fluxes is applied to such materials as ammonium chloride, zinc chloride, salt, borax, and boric oxide. A second class of materials, usually called deoxidizers, includes substances, such as metallic phosphides, sub-oxides, carbides, and bo-rides, that reduce the metallic oxides present in the metal. A third class includes various compounds that are molten and non-volatile at the temperature of the molten metal and are used primarily to protect the surface of the metal from the action of the furnace or exterior atmosphere; to this class belong such mixtures as lime and fluorspar, lime and soda ash, various minerals, etc. In some cases these protective layers may act in a manner similar to the metallurgical fluxes and dissolve or unite with the oxide impurities of the metal, but as generally employed this latter action is negligible since there is little opportunity for the coverings to come into contact with more than the surface of the metal, and hence they are without action on the body of the molten mass. The use of fluxes is the result of factory experience and tradition, but an extensive study has not been made of the chemical, and physical actions that occur or the effects of these actions on the properties of the metal. It would seem necessary in any successful study of metal fluxes

Jan 10, 1920

By D. N. Dietz

A method for determining average reservoir pressure is presented, which is simpler to apply than that devised by Matthews. Brons and Hazebroek. For bounded reservoirs, identical results are obtained if stabilized-flow conditions prevail. The present method yields inferior results in the transient state. The method can, with a slight modification, also be used for water-drive reservoirs. INTRODUCTION In the method proposed by Matthews, Brons and Haze-broek' for determining average reservoir pressure in a multi-well reservoir, the cumulative production (the production time of each well) enters twice: once when the buildup is plotted against In (t + t)/At to arrive at p*, and a second time when the correction, p*-p is determined with one of the several formulas for differently shaped drainage areas. Once a steady state has been attained, however, the previous production history should be immaterial. The same pressure distribution could have been arrived at after different cumulative productions of the individual wells. In principle, therefore, it should be possible to determine average pressures without referring to cumulative productions. In the following paragraphs an expression is presented for the difference between the pressure in a producing well and the average pressure of its drainage area. Then the build-up time needed to overcome this difference is indicated. CASE OF A CIRCULAR DRAINAGE AREA AND A CENTRAL WELL PRESSURE DISTRIBUTION BEFORE SHUT-IN The general differential equation of radial flow (see Muskat, Eq. 10.2) may be written In the steady state, the rate of production of the well is equal to the rate of expansion of the fluid contained in the the drainage area; thus

Jan 1, 1966

IT does not seem practicable to review all the other specialized curricula that have developed in the mineral industries field in so much detail as has been given for petroleum. Nor is it easy to draw a definite line between true curricula, leading to a designated degree in the special subject, and options, which may range from the mere substitution of one or two courses for others in the final years to differences so extensive as almost to amount to separate curricula. Even to attempt to catalogue all the options that have been offered at one time or another would require too much space. The remainder of this discussion, therefore, will be confined to three topics which seem to be of major importance. Mining and metallurgical curricula will be covered in a later chapter. GEOLOGY The first, from the historical view, is geology in its relation to the mineral industries. Previous chapters have made clear that in the early years of mineral industry instruction in the United States economic geology and mining engineering so overlapped one another that men who were by, training and experience economic geologists were appointed professors of mining, while men who had graduated as mining engineers sometimes developed into professors of geology. Even today men whose basic training was in geology as a pure science, and who perhaps took a doctor's degree in that subject, have attained such distinction in the mineral industries as to be universally accepted as "mining men," and their right to be regarded as mining engineers would- not be questioned, even though they did not take a degree in engineering. Nevertheless the distinction does exist, and has been made a concrete reality in recent years by the enactment of

Jan 1, 1941

By G. F. Loughlin

The subject of this lecture might well have been assigned to an economist or banker rather than to a geologist, but, as it was deliberately assigned to me, it is to be treated from a geologist's viewpoint. The term precious metals ordinarily includes the platinum group as well as gold and silver. Platinum, like silver, has had a great decline in price during the last few years, but has not been a medium of exchange and therefore has aroused comparatively little comment. Its relation to price level is like that of commodities in general, and will be dismissed without further comment. Of the two precious metals used as mediums of exchange gold, because of its adoption as the basis of most monetary systems and because of its threatened shortage in the near future; has been a subject of general concern to governments, financiers, and economists; silver, on the other hand, which has flooded the market of late has brought forth cries for help, direct or indirect, from producers and to a less extent from the largest users, especially China, whose purchasing power has been greatly curtailed, but it fails to arouse the interest that gold does. Many predictions have been made by economists, bankers, and others regarding future supply of gold and its effect on prices but the differences among these predictions are about as many as the number of prophets. Since gold is the standard by which the value of commodities as a whole is to be measured, it would seem that the greater the ratio of gold supply to commodities the higher the price level and vice

Jan 1, 1932

By Price E. R.

The coal industry was beset with work stoppages and strikes throughout the year, and there was some loss in markets to oil and gas. These conditions, along with the mild decline in industrial activity, the steel strike, and the reduction in exports, contributed to an unfavorable year for the industry. All coal mines are working three days a week at the time of writing, and in estimating production for the year, it will be assumed that the mines will continue to work on that basis through December. Total production of bituminous coal in 1949 is estimated at 420 million tons, which is 179,518,229 tons under the production in 1948. Anthracite production is expected to reach 39,400,000 tons as compared with 57,139,948 tolls in 1948, a loss of 17,739,948 tons. Coal stocks, as of January 1, 1949, were 69,373,000 tons but at the end of the year will have dropped to approximately 22 million tons. Regardless of the difficulties during the current year, the industry has made substantial

Jan 1, 1950

By R. R. Hawkins

PEoperly designed tubing strings make it possible to continue the flowing life of wells beyond the stage where ordinarily they would be put to pumping. Wells no longer able to flow through 2-in. tubing can be made to produce through smaller tubing if conditions within the well are carefully studied and correctly designed strings are installed. In this way, pumping expense may be postponed and in some pools it is within reason that the entire recovery may be obtained by natural flow if maintenance of pressure is practiced. Infrequent tubing changes would be necessary but their cost would be much less than that of installing and maintaining pumping equipment. If small wells are to be made to flow naturally, careful consideration must be given the actual lifting mechanics within the string, so that fairly accurate knowledge of reservoir conditions, especially pressure, is essential. Wells producing between 5 and 25 bbl. daily are classified here as "small wells." Exponential Flow A maximum of the energy contained in the expanding gas must be employed to do useful work if natural flow is to be continued. It is evident that adiabatic expansion would defeat this purpose, therefore the velocity of the gas must be held down to a minimum in order that isothermal expansion may be approached. Of course, true isothermal expansion would not be obtainable in an oil well, hence the use of the term "exponential." 1 Obviously the closer the approach to isothermal expansion, the more efficient the lift. Experiments by the U. 8. Bureau of Mines² have shown that for isothermal expansion to take place in a gas well where water is being produced, a definite relationship exists between the depth of the well and the minimum operating pressure. The latter must be such that the tubing fill-up, if static conditions prevailed, would be equivalent to 14 per cent of the distance between the top of the fluid inside the tubing and the tubing head. It has been observed that variations in this essential ratio

Jan 1, 1932

By Nick A. Hasenack, Heinz Kister, Rolf B. Vogel, Kees H. van Toor

A full survey of the laboratory and blast furnace tests carried out on two types of acid pellets is given. From the lab tests it appears that type B has a better low temperature disintegration index and a lower reducibility index than type A. The chemical composition and swelling indexes do not differ for both types. From the blast furnace test periods, carried out with a charge of 45% of pellets and 45% of sinter, it follows that both types of pellets lead to the same pig-iron production, blast furnace permeability, and blast furnace dust production. It also can be concluded that type B pellets cause a significantly higher coke consumption.

Jan 1, 1977

RESEMBLING in some respects the enterprise at R Chuquicamata is that of the New Cornelia Copper Co. at Ajo, Arizona. Controlled from its inception by the Calumet & Arizona Mining Co., New Cornelia became a unit of the Phelps Dodge Corporation when the latter absorbed the Calumet & Arizona company in 1931. Both Ajo and Chuquicamata are situated in low mountains in extremely arid desert country. Both ore deposits consisted-the past tense is used advisedly because the oxidized ore has nearly all been mined at Ajo-of a horizon of leachable oxidized ores overlying sulphide or concentrating ore. The principal technical problem in each case was the development of a method for treating the oxidized ore. In both instances the capping of waste rock was comparatively thin and power-shovel mining in open cuts was the obvious method of exploitation. Nature had smiled on neither place in the matter of climate. Though Ajo does not have the persistent winds for which Chuquicamata is notorious, the comforts of living are largely artificial. And it is only fair to emphasize that at each place the mining companies have achieved remarkable success in providing these comforts. Of course, in point of size New Cornelia must be content with the inferior role. From May, 1917, when production was started, to the middle of June, 1930, the company leached 16,368,000 tons of oxidized ore, thereby virtually exhausting the ores of this class. Up to the same date, about 15,000,000 tons of sulphide ore had been mined, and a rough estimate gives 170,000,000 tons remaining in reserve. The total tonnage does not loom very large in comparison with Chuquicamata's billion tons; but it is exceeded by similar figures for only four of the Porphyry group.

Jan 1, 1933

By G. R. Mansfield

THE third year of Government exploration for potash by the U. S. Geological Survey and the U. S. Bureau of Mines under the authorization of the act approved June 25, 1926 (Public 424-69th Cong.) is drawing to a close. The results thus far obtained are thought to be sufficiently interesting and satisfactory to justify the presentation of a brief pre¬liminary account of the work. REVIEW OF EARLIER EXPLORATION The general geologic similarity of the Permian basin of Texas and New Mexico to the potash field of Germany had long ago suggested the possibility of the presence of potash salts somewhere in that basin, but petroleum exploration was then making little headway there and the necessary data could not be obtained. The discovery by Udden in 1912 of potash in brine from the Spur well in Dickens County, Texas, was the first direct evidence of its presence. In 1915-17 the U. S. Geological Survey drilled a test well with standard tools at Cliffside near Amarillo, but failed to find potash. Nevertheless, an observer has been kept in the field, at first in cooperation with the Texas Bureau of Economic Geology but since 1922 by the Survey alone, to secure data and samples from oil and gas tests. Since the discovery of oil in Reagan County in 1923 exploration by drilling has been rapidly extended to many parts of western Texas and southeastern New Mexico. The identification of the potash-bearing mineral polyhalite was first announced by the Geological Survey in June, 1921, the material having come from cuttings from the Bryant well in Midland County and the Burns well in Dawson County, Texas. Successive discoveries and announcements of similar purport aroused widespread interest in potash exploration, which culminated in the action by Congress already noted.

Jan 1, 1929

The opening session was held on Tuesday evening, June 28th. Mr. F. S. Witherbee, of Port Henry, a member of the Local Committee, welcomed the Institute as follows: Mr. President and Gentlemen and (if I my also add) Ladies of the Institute: In the absence of the Chairman of our Local Committee it is my pleasant duty to give you a cordial welcome once more to the shores of Lake Champlain. I think some fourteen years have passed by since we last had the pleasure of receiving you at a meeting in this vicinity ; but the pleasure of that meeting still lingers in our memory; and the profit which we derived from your discussions and from your presence with us has made us heartily desirous to have you here again. If the truth must be known, we were for a time much embarrassed by the difficulty of providing adeqriate and comfortable shelter for the large number of friends whom we hoped (and, as this assembly indicates, had good reason for hoping) to receive. But the liberality and zealous co-operation of the Delaware & Hudson Canal Company and its hotel manager, in offering to open Hotel Champlain, at no little inconvenience, before the usual time, presented a solution of this difficulty, provided the date originally proposed for the meeting could be changed to a week later. This change was duly authorized; .and I think you will all agree with us that it was wise.. At all events, I am sure, I now need offer no apologies for the roof which covers yau. During the fourteen years which have elapsed since your last visit to us, great strides have been made in the industrial development of this country. The meetings of the Institute, held from one end of the land to the other, have permitted you to witness the transformation of small hamlets? like Birmingham, Ala., into populous and thriving industrial centers. You have seen the Minnesota and the

Jan 1, 1893

By C. C. Henning

In any line of human activity logical handling requires an amount of attention to each phase that is in keeping with the importance of that phase. In the complex and rapidly changing field of modern ferrous metallurgy it is difficult to allot the proper degree of attention to the various subjects, and it is not surprising that one or more subjects of major importance should for a time be neglected. Bessemer steel is a good example of a neglected subject. It is largely taken for granted, inferior physical quality is assumed for it, and there is a • lack of interest in its technical development and commercial application. Availability of supply is limited. In spite of this technical indifference, limited source and lack of commercial exploitation, bessemer steel constitutes a large volume of tonnage in daily use. There is a fairly prevalent idea even among technical people that bessemer steel survives mostly because of low cost and by reason of a dwindling residue of applications sufficiently common to permit of its use. The difference in cost between bessemer and open-hearth steel is governed largely by the relative cost of manufacture of pig iron and the market price of steel scrap. During the past four years there have been long periods of time during which the price of steel scrap was low enough so that open-hearth steel was considerably lower in manufacturing cost than bessemer. As to application, it may be pointed out that thousands of tons of this material in the form of bessemer screw steel are applied for moving parts in automotive and other equipment. Some forging work and considerable heat-treating, particularly carburizing, is performed on this grade. From an economic standpoint the most effective contribution of bessemer steel lies in its free machining qualities. It is by far the freest

Jan 1, 1935

By G. W. Jarman

The purpose of this paper is to present briefly a description of some of the special methods of separation or concentration, either singly or in combination with others, and to give certain operating data and examples. Explanation of the usual methods of large-production mill treatment, such as flotation or wet tabling, or of chemically treating industrial minerals, is not included in the scope of this paper, although one of these methods might be, in certain instances, augmented by one or more of the special methods that will be enumerated herein. Description of these special methods will be centered on magnetic separators, electrostatic separators and air flotation or air tables. Magnetic Sepaeatohs In general, separation is achieved by exerting upon a particle some kind of force opposed to gravity, either directly or at an angle. For example, in the Wetherill or cross-belt type of magnetic separator some particles are lifted vertically from the others because they have been exposed to a force to which they respond more readily than particles of lesser magnetic susceptibility. Of course, there is a limitation to this vertical rise, for the particle must be of a high enough susceptibility to receive a magnetic force greater than the 980 dynes per gram of gravitational urge. To overcome this limitation, the induction type of magnetic separator was developed, so that it is only necessary to instill, say, 30 to 60 dynes per gram instead of the 080, to cause a deflection away from the vertical in falling, and that deflection can be used advantageously when falling by inserting a dividing knife-edge. The induction magnetic separator (Fig. 1) has become a fairly well known method of concentrating and purifying. For example, abrasive grain was among the materials that did not respond to the previously best known type of magnetic separator, such as the Wetherill type, and the development of the induction magnetic separator in the plant of a

Jan 1, 1942

By R. S. Botsford

SPECULATION as to when and under what conditions mining may be resumed in Russia by foreign interests is becoming more interesting. Circumstances have changed so completely that all new projects must give careful consideration to the conditions as they exist at this time. For example, it is now estimated that a certain copper company in Russia can produce copper and put it on board ship at seaboard for 8 1/2c. per lb., crediting the copper with the value of precious metals contained. It is further estimated that in some places gold can be produced at a cost of about one-half of its value; platinum can be produced even more advantageously. Transportation, which is absolutely necessary for mines of coal, iron or manganese ore, as well as for an industry consuming either coal or coke, is not so essential for the operation of a gold or platinum dredge when the dredge has once been put into operation; after that, food is the principal material for which transportation must be provided. During 1922 the operators in the Urals, who had combined in a so-called platinum trust, expected to produce about 2340 lb. of crude platinum but the amount actually recovered during that season was reported as only 1620 lb., most of which came from hand workings; Nicolo Pavda had the principal dredges in operation during that year. In preparation for 1923 operations, about $400,000 worth of repair parts were obtained in England. At least two American-built dredges and one Putiloff dredge are reported in operation at Nicolo Pavda and it is supposed that most of the better dredges in the platinum district are now working.

Jan 12, 1923

By H. A. Buehler

The Ozark region occupies a large part of the southern half of Missouri, the northern portion of Arkansas and comparatively smalll areas in northeast Oklahoma, southwest Kansas, and southern Illinois. It is a roughly elliptical plateau which has been deeply dissected by stream erosion, and which slopes imperceptibly into the prairie regions to the north, east, and west, but which terminates rather abruptly along the Arkansas River on the south and Tertiary lowland to the southeast. The Boston Mountains extending for a distance of some 200 miles (321 km.) along the Arkansas River rise to an elevation of 2000 ft. (609 m.), forming the most prominent topographic feature of the region. The so-called St. Frangois Mountains in St. Frangois, Madison, and adjoining counties in southeast Missouri, form a prominent but more restricted topographic feature, the highest point rising to an elevation of 1800 ft. (548 m.). The remainder of the region is largely a plateau area varying from 800 to 1500 ft. (243 to 457 m.) in elevation. Stratigraphy The region is underlain chiefly by sedimentary formations, which outcrop in roughly concentric bands around a comparatively restricted area of igneous rocks in the St. Frangois Mountain district. Although located geographically near the eastern edge of the Osarks, the St. Frangois Mountains have apparently suffered the greatest orogenic movement and the lowest formations of the succession are exposed in their immediate vicinity. The various sedimentary formations of the region do not show any considerable metamorphism and have suffered little change since consolidation. With the exception of a few basic intrusions in Ste. Gene-vievg County and a pegmatite dike in Camden County, Missouri, there is no evidence of igneous action, since the first sedimentary beds were deposited.

Jan 1, 1918

By E. M. Bennett

HISTORY In 1923 John Campbell Miles discovered the Mount Isa deposit after finding and submitting for assay some “unusual and heavy rocks”. Six months after submission he received the assays of his original samples which indicated high lead-silver values. The deposit area was isolated and unknown geographically and not served by even a rough country road. The isolation of Mount Isa coupled with the depression years had a strong influence on the rate of development of the area. These two factors resulted in a slow amalgamation of the early individually held leases and the lack of ready finance to begin serious mining of the deposit. Initially, surface lead-silver-zinc mineralisation was proved and diamond drilling to shallow depths showed the presence of a viable orebody. Limited underground development work was initiated and open cutting associated with glory holing commenced. Due to the metallurgical problems associated with the ore and due also to unsuspected change in metallurgical conditions as the ore deepened into what is known today as the transition zone, major problems of finance were recurring at frequent intervals. Despite low metal prices the development of the mine continued due to continuing infusion of capital. During the 1939-45 war years a surplus of lead was being produced in Australia, but a grave shortage of copper was apparent. About this time copper ore had been found to the hanging wall of the then known major lead orebodies. At the request of the Australian Government, lead production ceased and copper production commenced.

Jan 1, 1970