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By A. L. Engel

[This report describes preliminary tests of samples from six deposits of oxidized copper ores .in Nevada. The tests for the most part were confined to laboratory-scale acid leaching to extract the copper.'The exceptions consisted of flotation tests to demons' ate the possibilities of treating the ore by that method. The samples tested were representative of oxidized copper ores from six counties in all parts of Nevada. The results obtained by the preliminary tests described were indicative of the extractions of copper to be expected, In the five leaching experiments, the approximate consumption of acid was also indicated.]

Jan 1, 1953

By Paul Thurlow, Richard K. Lipscombe

The measurement of deflection of designed diaphragm walls is critical for near real time information to assess wall and soil behaviour as the internal area is excavated in a controlled manner. Data enables the site team and designers to check performance of the design, which is linked to safeguarding the site and the external stakeholders.This paper documents the use of Shape Accel Arrays at the Tottenham Court Road Western Ticket Hall during excavation and propping within the diaphragm wall for the Crossrail project. It shows how the data obtained was used within the site settlement management plan to assist in the control of the works and the information used for Value Engineering purposes that benefitted the project.The use of Shape Accel Arrays for measuring the deflection of retaining walls is not commonplace in the UK construction industry, with the Tottenham Court Road Western Ticket Hall being one of the first times they have been used in such a way. A detailed analysis of the data obtained from the instruments has been undertaken, and compared to the results obtained from the manual inclinometers that were read next to the SAAs. The advantages of the relatively new SAAs have been discussed, as well as other applications of the instrument.

Jan 1, 2017

By Donald Towse

Portland cement is a basic building material in every country in the world, and, fortunately, the raw materials required in its manufacture are widely distributed. It is a low-priced bulk commodity (price one cent a pound or less, with a density of 100 pounds per cubic foot.) Table 1. Approximate price per pound of selected mineral products. Copper 48 cents per pound Aluminum 27 Lead and zinc 15 Asbestos 3 to 18 Pumice 6 Sulfur 2 Bauxite (abrasive) 1.8 Barite 1 to 1.6 Cement 1 Primitive regions may get along without any Portland cement, but most countries use some, and it is one of the most widespread building materials, even if used in small quantities. Use of cement begins early in a country's development, and, because of local availability of raw materials, cement manufacture is one of the first heavy industries many countries desire. Use and manufacture of cement usually precedes other industrial materials such as steel and heavy chemicals, and consumption levels off for a long period during development of infrastructure and an economic base. With a mature economy comes a very high consumption. Per capita consumption varies ten times or more between nations (Figure 1).

Jan 1, 1970

By Andrew Port, Ali Ghandeharioon

Nonlinear seismic deformation analyses using the finite difference program FLAC were performed for a wastewater treatment plant to estimate foundation displacement and performance of two proposed trickling filters during the 2475-year event design earthquake. The effective stress based constitutive model UBCSAND, which captures the cyclic behavior of both the “sand-like” and “clay-like” materials, was used to model the dynamic response of the soil strata. Dynamic analyses of the site indicated that in absence of ground improvement or deep foundations beneath the proposed trickling filters, those structures would undergo horizontal displacements in excess of 1 m and short-term differential settlement gradient of about 400 mm over 50 m as a result of seismic and post-seismic settlements. Three mitigation options were considered for limiting the seismic displacements and differential settlement gradients of the proposed trickling filters. These alternatives include vibro-replacement stone columns, vibro-replacement stone columns plus supplementary cutter soil mixing (CSM) configurations, and pile foundations. Various layouts for each mitigation option were considered including the lateral extent of the ground improvement, CSM walls and pile spacing. Seismic horizontal and vertical displacements of the proposed structures as well as post-earthquake consolidation settlements due to dissipation of excess pore water pressures in soil layers were assessed in all the analysis alternatives. The analyses indicate that all the alternatives considered have the potential to provide a comparable level of seismic and post-seismic performance. However, for similar performance levels, the ground improvement options need to extend well beyond the edges of the proposed structures, while the piles can be limited to just beneath the footprint of the structures. INTRODUCTION Annacis Island Wastewater Treatment Plant (AIWWTP) is owned and operated by Greater Vancouver Sewerage and Drainage District and services a population of approximately 1 million people in Vancouver, British Columbia. Wastewater is generated by residential, commercial, and industrial sectors and the treated effluent is discharged to Annieville Channel of Fraser River on the south side of Annacis Island. AIWWTP is located on a 51-hectare site and was commissioned in 1975 as a primary treatment plant, but has had two major expansions to meet the population growth needs, and to improve the treatment process efficiency through the provision of secondary treatment of the liquid stream. The current expansion includes construction of additional solids contact tanks and secondary clarifiers. Future expansions include the construction of proposed additional trickling filters. New expansion structures are required to be designed for post-seismic operation after the 2475-year event design earthquake.

Jan 1, 2018

By R. Altındag, D. Akbay

The point load index is a simple, fast, and inexpensive method for determining rock strength and can be applied both in the field and in the laboratory. There are, however, some disadvantages and limitations to the method, and the test results can be affected by the person carrying out the test, the rock characteristics, or the test device. In this study we describe an investigation into how the point load index value is affected by the shape of the conical platens used in the test. Point load index tests were carried out using different devices fitted with conical platens of different spherical radii, and on a modified device which circumvented the limitations/disadvantages. It was seen that the point load index value increased as the platen radius increased, as expected. In the case of testing using non-standard conical platens, an equation is proposed to normalize the point load index value with respect to the standard spherical radius value.

Nov 1, 2021

The Telfer Underground sublevel cave (SLC) Operation is located approximately 850 m below surface. The cave was designed to propagate through an old decline which was initially used to monitor the cave. There was a requirement to install air blast plugs at two locations in the old decline in order to isolate any potential air-blasts from the active workings in the event of the rock mass collapsing into the cavity. There was a further requirement for an air-blast plug in another section of the mine where there was a risk of the cave intersecting an old workshop and providing an air-blast pathway through an abandoned incline. The design criteria for the plugs was that they should withstand the design air blast loading, be free draining, cost effective and easily constructed with the mining expertise available on site. A plug consisting of grouted mullock was considered robust and least challenging to construct. For the purpose of estimation of maximum air pressure on plugs, it is supposed as a worst case that the rock above a cave falls as an airtight piston onto the top of a muck pile, forcing air into it and also mine workings intersected by the cave. Airflow through the muck pile is governed by Ergun's equation for turbulent flow. In a time-stepping integration scheme, transient air pressures and velocities are calculated according to equations of thermodynamics, in the cave and at intervals along intersected drives by means of a finite difference spatial discretisation. The ability of plugs to withstand computed pressures is assessed by finite element elastoplastic analysis. This paper outlines the rationale for potential air blast loading, calculation of transient air pressures, plug design and analysis of plug behaviour. The plug construction method is also discussed.

Nov 25, 2010

By Charles L. Ross

A successful placer mine is being operated by the E. T. Fisher Co. on Rock Creek in the South Pass mining district at Atlantic City, Wyo. About 2,800 cubic yards of gravel is dug daily by a gasoline-driven dragline shovel with a 1 1/4-yard bucket and washed in a movable plant with a gold-dredge trommel and standard-dredge sluice boxes; the total cost is about 12 cents per cubic yard. The gold-bearing gravel occupies a narrow valley between two low ranges, of hills. The ground is covered by brush and willows, which are cleared of in the fall by burning after the leaves have dried. The elevation at the mine is 7,600 feet above sea level.

Jan 1, 1935

By W. C. Risley

IN the year 1933, workings at the No. 12 colliery, New Waterford, of the Dominion Coal Company, Limited, had advanced to a point where additional ventilation would soon be required. Furthermore, development of the mine was being .made to practically double the output of coal. Consequently, authorization was given to sink a shaft to the workings. The location selected is on the west side of the mine, about one and a half miles from the slope mouth and on the Low Point shore, some 250 feet from high-water mark. The cliff at this point is 40 feet high, with the land rising on a slope of about 5 per cent to the shaft. Figure 1 shows the location with reference to the colliery workings. The strata through which the shaft was to be sunk were pretty well known from diamond-drill borings previously made, and it was believed that water would be encountered to a depth of at least 250 feet to 300 feet. It was planned, therefore, to seal-off the water by the pumping of cement grout under high pressure. This method was considered to be the most economical means of handling the water during sinking, and would also result in a permanently dry shaft. Figure 2 shows a cross-section of the strata. The permanent shaft hoist and fan were to be electrically driven, which would necessitate the construction of a transmission line between the colliery and the shaft; therefore, it was arranged that the sinking equipment would have electric drive. As all equipment, materials used in construction, and supplies were to be hauled by truck, a roadway 1,800 feet long was required from the main highway to the site, and as heavy loads would be hauled during the fall, winter, and succeeding spring, this road was ballasted with 18 inches of clinkered material obtained from a burned culm bank one and a half miles distant. Actual field work was begun by the Company's own forces early in October. Work preparatory to sinking-in addition to the roadway and trans-mission line-included the construction of the reinforced-concrete shaft collar and fan drift connection; the permanent timber headframe (which was to be used also as the sinking headframe); the permanent reinforced-concrete building to house the shaft hoist and fan drive; and the erection of temporary buildings and installation of all equipment for sinking and lining the shaft and for cementation.

Jan 1, 1936

By Walter R. Storms

This paper , which describes the mining methods and costs at the Atwood copper mine in the Lordsburg ( Virginia ) Mining District of Hidalgo County , N. Mex . , is one of a series being prepared by the Mining Division of the Bureau of Mines on mining practices , methods , and costs in various mining districts of the United States . The mine and surface plant are situated in the west half of sec . 7 , T. 23 S. , R. 18 W. , about 3 miles by road southwest of the center of Lordsburg , near the old abandoned townsite of Valedon ( see fig . 1 ) . The main line of the Southern Pacific Railroad passes through Lordsburg , as does the paved eastwest U. S. Highway 70-80 . A spur line of the Southern Pacific ends near the mine . A good graded road connects the mine with Lordsburg . The following pages present a brief history of the district , describe the geology , and outline methods of prospecting and exploration, including sampling and estimations of tonnages and values . Development, and mining methods are explained , and transportation , ventilation , drainage ,. safety measures , and organization are described . The wage scale and costs of development and mining comprise the corrcluding sections of this circular .

May 1, 1949

By D A. Williams, J C. J Boshoff

The properties of tailings that emanate from laterite nickel processing plants are significantly different to most other mine tailings. They typically comprise a mixture of fine materials that are made up of altered clays, chemical residues and salts. Neutralisation processes that are undertaken prior to tailings discharge result in a high proportion of gypsum in the tailings. The salinity of the pore fluid is commonly higher than 140 g/L of salts, dominated by magnesium sulfate. Hydraulically-placed tailings that undergo solar evaporation typically reach dry densities of less than 1 t/m3 of insoluble solids. In situ water contents after many months of drying may be as high as 80 per cent, and peak undrained shear strengths are unlikely to be greater than 20 kPa.This type of material is not conducive to upstream raising, from both a practicality and overall slope stability perspective. Even at rates of rise of less than 1 m/a, it is difficult to effect upstream raising on unaltered laterite nickel tailings. However, the authors have successfully designed and implemented upstream-raised laterite nickel tailings storage facilities. The upstream raises have been formed from both imported natural materials and air-dried and compacted tailings borrowed from the tailings beaches.Drying and associated strength gain has been achieved through various means of mechanical intervention, repeatedly exposing a zone of tailings to the atmosphere for evaporation. Field trials have been undertaken to optimise the approach, and the findings from the trials have been implemented in practice to allow stable upstream raises to be constructed. The cost savings and reduced environmental impact compared to high-volume downstream raises have been significant.CITATION:Williams, D A and Boshoff, J C J, 2015. Upstream raising of laterite nickel tailings storage facilities, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 271–280 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By Steven J. Schatzel, Kayode M. Ajayi, Bo H. Kim, Zoheir Khademian, Gabriel S. Esterhuizen

The stability of shale gas wells drilled through current and future coal reserves can be compromised by ground deformations due to nearby longwall mining. Depending on the longwall-induced rockmass permeability, the high-pressure explosive gas from the damaged well may reach mine workings and overwhelm the mine ventilation systems. This study uses geomechanical models to estimate the rockmass permeability induced by mining. A two-panel longwall model of a deep, 341-m-cover mining site in southwestern Pennsylvania is constructed in 3DEC to explicitly model the rockmass by a discrete fracture network (DFN) technique. Stress-induced fracture apertures and permeabilities are calculated across the model and are validated against permeability measurements. A fracture flow code (FFC) is developed to use these results to predict potential inflow to the mine should a gas well breach occur. One hundred DFN realizations are simulated, and the results show that for a gas pressure of 2.4 MPa, the average of the predicted inflow rates to this deep-cover mine is 0.006 m3/ s, significantly lower than the average inflow of 0.22 m3/ s for a shallow-cover mine (145-m deep) studied in the previous work (Khademian, et al. 2021). The result can help assess the potential hazards of a shale gas well breach for mine safety and evaluate the ventilation requirements to mitigate the risk.

Jun 19, 2022

By M E. Watson

Minimising dilution and ore loss is an important part of ensuring profitability of a gold mining operation. White Foil open pit gold deposit is a low-grade deposit and therefore managing ore quality is a high priority. Ground movement through blasting can displace ore and waste boundaries up to 10 m from their in situ location and therefore requires stringent ore movement monitoring and adjustment. There are currently only two options for monitoring blast movement – utilising visual targets (commonly lengths of polypipe) but this has widely been replaced by electronic blast movement monitors (or BMM). Regardless of the technology used, the basic principle is to compare the pre- and post-blast locations of the targets to determine the movement of the rock mass during blasting, which is then used to determine the final location of ore and waste boundaries.The Blast Movement Technologies (BMT) BMM system has been used at White Foil since June 2014. The system has been effective and reliable during that time; however, the annual cost of using the BMM system is greater than other monitoring alternatives. As such, the open pit geology team conducted a study comparing the BMM system against the conventional polypipe technique. The objective was to quantify the profit and loss that would occur based on the ore block transformations from both methods. Eight blasts were selected where polypipes were installed in additional holes adjacent to the BMM monitoring holes. The resulting movement vectors from the respective methods were used to create post-blast ore blocks by transforming the in situ ore blocks. While polypipe is a cheaper alternative, the BMM system tracks ore and waste boundaries more effectively resulting in better quality control, enhanced ability to minimise dilution and ore loss thus maximising profit. For these eight blasts, it is calculated that the BMM system resulted in A$664 978 extra profit through a reduction of ore loss. The total cost of a yearly BMM package was recovered in the first two blasts of this study. The primary reason for the difference is that polypipe had a poor recovery rate of 32 per cent compared with 92 per cent for BMM at White Foil. Therefore, the data used to transform the ore blocks was less representative, resulting in inaccurate post-blast ore block boundaries when using polypipe.CITATION:Watson, M E, 2017. Blast movement monitors or polypipe? A study into cost-effective blast movement monitoring at White Foil gold mine, Western Australia, in Proceedings Tenth International Mining Geology Conference 2017, pp 433–440 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By Ed Mchugh

NIOSH researchers collected basic data from two blast rounds at the SSX-Steer Mine as a component of a larger study on controlled blasting, the goal of which is to reduce injuries from falling rocks in underground mines. Drilling and blasting procedures at the mine were observed. Rock mass property data were collected, a program of seismic monitoring and analysis was conducted, and 3-D laser survey scans of the workings before and after each blast were performed. The geologic data showed that the rock mass quality was characterized as poor to very poor. It was essentially uniform within the panels examined. The recorded seismic data indicated that fill material acted as an effective damper to seismic energy. The pre- and post-blast laser scans showed both over-break and under-break conditions, highlighting the problems associated with blasting a weak rock mass. By comparing the achieved results to the intended design, potential improvements in the drilling and blasting practices can be identified. Comparison of these data with similar data from other mines will help define how various combinations of rock and fill behave during blasting. Through studies such as these, data collection procedures and analysis techniques can be refined. An ultimate goal is to develop blast procedures tied to rock mass characteristics that can minimize damage to rock in the perimeter of the opening, limiting the amount of loose rock and improving the safety of miners.

Jan 1, 2007

By Ronney Rodrigues Silva, Renata Mendonca, Gabi Knesel, Cathrine Monyake

Locus Mining is working side-by-side with a prestigious iron ore company to evaluate the addition of Locus ESG-friendly green flotation reagents with the primary goal of improving recovery and grade. In this paper, we will focus on the cationic reverse flotation application. The most “established industry” reagents for cationic reverse flotation are amine as the collector, starch as the depressant, and in some cases frothers are also used (among them MIBC, pine oil, others). Here, we evaluate the synergies of different classes of eco-friendly biosurfactants and industry-standard reagents during the cationic reverse flotation method. Exploratory research was done first with an analog sample under different pHs, eight different biosurfactants with starch and no-starch, and a customized DOE was used to perform 145 microflotation tests. The results show Separation Efficiency from 20% (baseline) to 50% (biosurfactant), and Selectivity from 3.27 (baseline) to 5.67 (biosurfactant). Optimized result conditions were then applied to the iron ore samples received from our client to perform flotation tests on a Denver Lab cell. Similar results were obtained by improving Separation Efficiency and Selectivity, which corroborate with the previous work.

Feb 1, 2025

By Irshad A. Rana

In a modern copper smelter, the capital cost of a sulfuric acid plant constitutes the largest single cost item of the total investment. It is thus essential to properly size the acid plant in order to reduce its capital cost and enhance the economic viability of a new smelter project. Whereas the off-gas from a smelting furnace is continuous and generally uniform, the gas flow from the Peirce-Smith converters is intermittent with significant fluctuations. The converters off-gas volume is dependent upon a number of interrelating factors. The most significant factors are the matte feed grade, the system air infiltration, the converter's size and blowing rate, the maximum number of converters simultaneously blowing and the gas cooling system employed. The acid plant size, therefore, is heavily influenced by the converter off-gases. Several of these factors are discussed, and their impact in determining the acid plant size is explored.

Jan 1, 1993

By S. M. H. Ahmadi, K. Barani, F. Moradpouri, R. Ghaedrahmati

As exploration is time-consuming, costly, and risky, determination of the erosion surface of a metalliferous deposit before geophysical surveying and exploration drilling might be very helpful. Geochemical haloes can be used to determine whether the erosion surface is supra-ore or sub-ore and thus reduce the risk of exploration operations. The aim of this investigation is to determine the erosion surface of the North ROK porphyry deposit (NRPD) in northwestern British Columbia in Canada using linear productivity (LP), which is the content of an element defining the halo multiplied by the width of the halo. A total of 2045 soil samples from the B horizon were analysed using ICP-MS for 36 elements, including Cu, Mo, Pb, Zn, Au, As, Ag, Ni, Co, Fe, and Mn. The data-set was snalysed to obtain the statistical parameters and the elements Cu, Mo, Pb, and Zn were chosen to calculate the linear productivity and the total linear productivity. These four elements were modelled using probability plots to identify and separate subpopulations in terms of anomalous haloes and background, including the threshold values of each subpopulation. The results of the probability plot modelling and thresholds values were then used to map the distribution of each element in a GIS to calculate the linear productivity. The total linear productivity indicated that the erosion surface is supra-ore. Finally, a 3D orebody model of the Cu, Mo, Pb, and Zn distributions was constructed using borehole data and used to validate the results.

Feb 6, 2023

By Y. Q. He

The dynamic behaviors of the air bubbles in the dense gas-solid fluidized bed have a significant effect on the performance of dry coal separation. The combined method of experimental measurement and numerical simulation were conducted to conduct the research of the mean diameters and rising velocities of the bubbles in the fluidized bed. The calculation models of mean diameter and rising velocity of the single bubble were proposed. The results indicate that the models of the mean diameter raised by Rowe (1976) and the rising velocity raised in this work could be used to predict the bubble dynamic parameters in gas-solid fluidized bed. With the Geldart B type of magnetite powder as the medium solids and while the gas velocity of 1.5Umf=U=2.2Umf, the mean bubble diameter along the bed height is 36mm<Db<45mm, and the mean rising velocity of the single bubble is distributed in 40~65cm/s. The results of experimental measurement, numerical simulation and model predication provide well agreements finally. Based on the uniform fluctuations of air bubbles diameters and their rising velocities, the separation experiments of 50~6mm dry coal using the mixture of 0.3~0.15mm magnetite powder and <1mm fine coal as medium solids were carried out. The results show that the probable error, E is 0.06, which indicates a good separation performance by using the gas-solid fluidized bed. Keywords: dense gas-solid fluidized bed, bubble dynamic behaviors, numerical simulation, separation performance

Sep 1, 2012

By C Samuelsson, Q Shu, A Lennartsson, F Gyakwaa, A Andersson, J Isaksson

The physico-chemical property, viscosity, is essential for pyrometallurgical processes and influences the settling rate of valuable metal droplets in slag, affecting the metal recovery. The copper slag from smelting furnaces typically contains between 1 and 2 wt per cent Cu, which equals to or is higher than in most sulfidic copper ores mined today, meaning the slag is a valuable resource for copper extraction. A low viscosity is desirable for slag-cleaning through a settling furnace where entrained droplets settle under gravity. One approach to control the viscosity is through the slag composition. The literature has limited data on the correlation between viscosity, slag structure, and optical basicity of iron silicate slag with FeO/SiO2, CaO, and Al2O3 as factors. Therefore, the present study evaluated the influence of these factors on viscosity and correlations with slag structure and optical basicity. The FeO/SiO2 ratio (at%/at%) and the CaO and Al2O3 content were altered in two levels, resulting in a two-level full factorial design with three factors. The study was done by synthesising FeO–SiO2–Al2O3–CaO–MgO–Cr2O3 melts, followed by water granulation. The melt structure of the samples was analysed with the help of Raman Spectroscopy. The viscosity was then estimated with a high-temperature rheometer using a Mo spindle and crucible. The results showed a correlation between the optical basicity, FeO/SiO2 ratio, and viscosity, where a high optical basicity and FeO/SiO2 ratio were beneficial for achieving a low melt viscosity.

Jun 19, 2024

By D. S. Kingery

The control of coal dust on coal tipples and cleaning plants has not been given the consideration that is afforded underground dust hazards. This apparent oversight is undoubtedly due to the general opinion that coal-dust accumulation in tipples or cleaning plants does not present the same type of hazard that it does underground. That this opinion is at least in part a fallacy has been proved many times, and the Bureau of Mines has on record many examples of explosions in tipples and cleaning plants.3/ In addition to this explosion hazard, coal dust is considered by sonic authorities to be injurious to the health of individuals exposed to it.4/ Obviously, it reduces visibility and contributes materially to accident hazards and the discomfort of the employees. Several companies have recognized this dust hazard and the advantages derived from controlling it; consequently, they have installed equipment to allay and control the dust on, their cleaning plants and tipples. The object of this paper is to. Summarize briefly some of the methods new in effect.

Jan 1, 1943

By R. L. Clayton

The Bagdad district is 67 kilometers west of Prescott, Arizona, (Figure 1). The area north of the Old Dick and Bruce Mines was originally mapped by Anderson, Scholz and Strobell between 1943 and 1945, (1). The region is perhaps better known for the Bagdad porphyry copper deposit of tertiary age. However, 2 to 5 kilometers south of this deposit are several small massive sulfide occurrences in a eugeosynclinal Precambrian greenschist environment. More specifically, in. the Bridle formation of the Yavapai schist series. Three of these mines - Old Dick, Bruce and Copper Queen - were mined by Cyprus Mines Corporation between 1957 and 1977, and produced nearly 2mm tons of 3.6% copper and 12% zinc. These deposits occur at the interface between andesite and rhyolite and are stratiform in character. Certain structural and textural properties of the Bruce orebody suggest that remobilization of the massive sulfides occurred at some period during the metamorphic history of the area.

Jan 1, 1978