The copper-bearing horizon of the Udokan deposit is composed of gray fine-grained quartzitelike sandstones. The principal nonmetallic minerals are quartz and feldspar. The ore complex is of bornite, chalcocite magnetite, pyrite, and chalcopyrite.The sulfide mineralization is nonuniformly distributed; together with fine disperse disseminations there are very rich sections, amounting in places to almost continuous sulfide ores. The textures of the ores are disseminated, with lens-shaped flecks, less often massive; the oxide ores are brecciated and filmy or crusty.The ores in this deposit are characterized by two main mineral parageneses, spatially separated and containing two varieties --magnetite--bornite-chalcocice and pyrite-chalcopyrite. Sulfide, mixed, and oxide types of ore are distinguished by their degree of oxidation. For working these, flotation enrichment with collective concentrate production is recommended. The quality of the concentrate from the chalcopyrite ores is less good than that of the chalcocite-bornite ones, and moreover, as the copper oxide content of the ore increases, the process of separating it gets more difficult.Analysis of the information on the distribution of components in ore varieties, obtained during surveying of the deposit, gave the following results:i) The magnetite-bornite-chalcocite ores are richer in copper; as the copper content of the ore increases, the magnetite content increases but the zircon content decreases.ii) The silver and bismuth contents of the ore increase with the bornite content.ill) The silver and gold are mainly associated with the chalcocite.iv) The h~n-tite andbarren sandstones have enhanced silver contents. v) Electromagnetic separation causes bornite to go into the magnetic fraction and chalcocite into the nonmagnetic fraction.The relations between the elements are important, and also their spatial concentration. In the deposit we can distinguish three sections containing ores of different qualities. 35Magnetite--bornite-~halcocite ores predominate in section I. In this section the relative copper oxide content is lower but its absolute content is higher.In section III we find the highest silver content; it is found that, in comparison with sections I and If, the silver content of the ore increases with the copper content.~e complex relations between the elements require us to estimate the commercial value of the extracted ore, and on the basis of the results to select the first section for working. However, in order to perform these calculations, we must devise a technology for processing the ore to give high concentration of the elements in the intermediate products and concentrates with sufficiently high extraction.Institute of Mining, Siberian Branch, Academy of Sciences of the USSR (IGD SO AN SSSR), Novosibirsk. Translated from Fizlko-Tekhnlcheskie Problemy Razrabotk/ Poleznykh Iskopaemykh, No. 2,

622.271In working the Kansk-Achimk coalfield, which has variable seam and overburden thickness, it has been found inefficient to use mechanical shovels with normal characteristics. The bucket capacities necessary are 80-110 ms. In the Soviet Union there is as yet no experience in the construction and use of such machines. On the other hand, in (for example) the USA, one basic model may have various modifications to the characteristics of the bucket and the jib length, so that when the geological conditions vary it is only necessary to change the bucket and jib.In connection with the problems arising in working coal deposits Iike those in the Kausk-Achimk field, we shall, in this article, attempt I) tO find the relations between the basic characteristics of very large mechanical shovels, 2) to establish the relatlon between the bucket capacity and jib length for one basic model, and 3) to determine characteristics for mechanical shovels with bucket capacity 80-II0 m s, suitable for conditions like those of the Kausk-Achinsk field, Mechanical shovels are designed for working overburden rock lying above the excavator horizon. In selecting their principal operating Characteristics we use the theory of similarity and dimensions [I-3]. The material available from foreign journals [4-6] on this problem is given in Table 1.To dlsplay the relations between the main characteristics of mechanical shovels, the data from Table I qy where q is the nominal bucket capacity in m s, qy is the altered bucket capacity in m s, ! is the nominal jib length in m, and ! y is the altered jib length in m.In cons~uctlng the theoretlcal L-q curve for a basic model, we shah take an excavator with characteristics close to the mean value (curve a).In [3] it is remarked that "when the jib and arm lengths are increased by 20-25~ the bucket capacity is usually left unchanged. For a greater increase in the jib and arm lengths (up to 60-85ob), the bucket capacity is reduced roughly in proportion to the square root of the ratio of lengths q~. -. r q. c2)while the working weight of the excavator increases proportionally to the cube root of the jlb and arm lengths." Following [3], from (2) we construct curves b (see Fig. 1) for the basic models with q = 60, 90, and 120 m s and L = 55, 64, and 66 m, which show that with increasing jib length the bucket capacity also Increases for the same basic model. This is true for all the basic models.Mining Institute, Siberian Branch of the Academy of Sciences of the USSR Electrical Engineering Institute, Novosibirsk.

Nonferrous and rare metals are mined mainly in deposits in which the ore bodies have complex structures and the composition of the ore is very far from constant. The ore bodies have irregular shapes with numerous branchings and pinch and swell are frequently observed. The "pattern" of the reserves is disturbed both within the ore body itself and in the veins or zones. The ore composition is characterized by the presence of several types and grades of varying commercial value, the processing of which requires a variety of beneficiation schemes.Open-cut mining of deposits of nonferrous and rare metals is performed by general or selective methods. The general method is widely employed owing to its simpllnity and therefore the relatively low cost per ton of ore. However, this method is not always effective: cutting and removal are accompanied by high losses and impoverishment of the ore, sometimes reaching 10 and 300, respectively. The simultaneous mining of different types and grades of ore leads to increased losses during beneficiation.Removal of the mineral with greater efficiency and lesser contamination of the ore is obtained by selective mining, particularly if systems of complex selective removal are employed [1]. We can then employ separate processing of the various ore grades in the beneficiation plant, thus increasing the extractable value per ton of ore by a factor of 1.5-2.5.In separate removal, the drilling and blasting work and the loading operations undergo maximum variations because the operational characteristics and procedures change. The mining equipment widely used in all ore quarries is employed for drilling and loading. Selective removal of the ore by excavators is performed by various scooping procedures and with various locations of the excavator at the face. The way in which a particular scooping procedure is performed depends on the skill of the operator rather than on the excavator's design characteristics. Even if the work is handled carefully, losses and impoverishment of the ore are inevitable because, as the bucket scoops up the broken rock, it "wanders" up the working face and captures material outside the ore body or the individual ore (rock) inclusions. Therefore the drilling and loading equipment used in most quarries does not permit selective working. The mining of highgrade ore and the reduction of losses of metal therefore demand new engineering solutions in this field.The most essential step in the working of complex faces is to change the scooping procedure; this requires the development of new loaders: the forces developed on the teeth of the bucket must enable it to "bite" at any level.The Mining Institute of the Siberian Section of the Academy of Sciences of the USSR and Gipronlkel' are developing loaders with "activated" buckets for underground working [2]. Similar machines are being designed abroad [3]. For example, the GSR-11 has a bucket with five picks, actuated by a compressed-air or electrohydraullc drive, with impact energy 4.5 kgm and impact frequency 940 per min. T...

The formation of an enriched intermediate product or lean concentrate from ores of nonferrous metals by separation of coarse classes without crushing, grinding, or beueficiation greatly reduces the capital and running costs and reduces the delay in the exploitation of new deposits.If there is a uniform distribution of the components by fragment size, use is made of electronic methods of separating ores; oscillator separation makes use of simple apparatus and does not require reagents [1, 2].An estimate of the effectiveness of the oscillator method of separation has been made for disseminated lead and lead-zinc ores. The ore-bearing strata of the deposit are composed of recrystallized and sheared carbonates and sometimes clay rocks. ,Mineralization in the form of sulfide streaks is confined to the quartzitic and sericitic parts.Our research program envisaged testing ores for separability and predicting the technology of processing the intermediate separation products.The ore was separated on a mock-up of an oscillator separator in the form of a disk feeder in which, at the ore exit point, were successively fixed an inductive oscillator transducer [3] with worMng frequencies of 13 and 56 MHz, and a gate-type separator controlled by the signals from the transducer with the aid of an electronic threshold circuit. The throughput of the separator was about 10 toas/h for material with a fragment size of 150-50 mm.To study the separability we selected and classified a sample of about 8 tons of lead ore. For separation we picked out about 2 tons of ore of the 150-50-mm class with a lead content of 8.17%.Separation yielded intermediate products containing 20 and 10% of lead, with 27% extraction from the original ore. Iron was concentrated preferentially in the tailings from the separator.The limiting lead content at the separator was found by visual inspection of the ore samples. To find the closeness of the correlation between the lead content of a fragment and the level of the signal from the transducer, and to choose the type of signal (amplitude or frequency) and the optimum frequency for the transducer, we investigated the recovery of ore specimens from 50 fragments of the 150-50-mm class.Signals from the inductive oscillator transducer from each specimen were measured at 5.28, 13.56, and 27.12 MHz. It was found that the moisture contents of the specimens had practically no influence on the signal. The greatest dynamic range (from 0.01 to 11.5 V) was observed for the amplitude signals (increment, change of voltage in oscillator circuit) at 13.56 MHz. There was a close correlation between the signal amplitude and the lead concentration in the specimens; the nonlinear correlation coefficient was 0.821 and the equation of nonlinear regression, according to calculations by the method of least squares, was a=--10.26 (lg U+0.6) +29.33 arctg (Ig U+0.61 ~15.22. where a is the lead content in per cent and U is the amplitude of the signal from the transducer in volts.From the analytical relations it was found that the minimu...

In attacking problems of optimization of blending systems it is necessary to estimate the technological efficiency of the blending units in the system and to determine the variability characteristics of the quality indices at their outputs. Azbel' and others [1,2] have suggested expressions for the variability characteristics (dispersion and correlation function) at the outputs of blending units, derived on the basis of the theory of stationary random functions. These expressions are used to study the blending stage taken separately and when the incoming random process of fluctuations of ore quality is stationary.In determining the laws of operation of the blending system we have to find and utilize the variability characteristics at the output of each stage. The solution of this problem with the aid of the expressions in [1] presents considerable difficulties and gives results close to the experimental values only when the randomprocess of quality fluctuation is stationary~ i.e., only when the conditions(where ms(t) is the expectation value and a2(t) the dispersion of the ordinates of the random process as a function of time) are satisfied [3].Real random processes generally are markedly nonstationary, and this is manifested by the presence of a trend of the average quality (violation of condition (1)) and a rise in dispersion with increasing length of realization of the process (violation of condition (2)). This means that the calculated values of the technological effectiveness (degree of blending) of blending units for real cases of nonstationary processes of quality fluctuation will be close to the actually observed ones only for estimation over brief realizations of the process, comparable with the capacity of the unit.Such an estimate is inadequate to determine the effectiveness of the blending system. If the blending system includes blending in the process of planning extraction of the ore as well as control of the mine transport operations in the blending regime, it becomes necessary to estimate the effectiveness of the system over a sufficiently long time, at least not less than a unit period of planning of extraction operations. In this case nonstationariness, such as a time trend, becomes crucial, because in optimization of the system parameters we must solve the question of how far and in what way this trend must be reduced by planning and control of the extraction operations in the blending regime. Thus we are faced with the problem of finding a method of reliable estimation of the technological effectiveness of a blending system with a real nonstatiouary process with long realization times.The authors have developed a method of estimating the variability at the output of the blending units, based on the use of the simplest of the equations in [1] and of the basic principles of the spectral theory of random functions.The main principle on which the mathematical apparatus of the method is based was described by Margolin [4]. Its essence is that any geological variable (in our case the quality index i...