Types Of Tailings Research Articles

English

The objectives of this project are to demonstrate the use of organic amendments to enhance the establishment and growth of grass on lead mine tailings and evaluate the effect of those amendments on plant uptake of metals. Two sources of compost and an organic fertilizer derived from municipal sewage treatment plant sludge were incorporated into two types of tailings near Desloge, Missouri, and the replicated plots were planted with grass. Both types of tailings (fine-textured flotation tailings and course-textured gravity separation tailings) contain elevated concentrations of lead (Pb), zinc (Zn), and cadmium (Cd). This project will be evaluated for three growing seasons. At the end of the first growing season, vegetative cover and biomass production were quantified, and tailings and vegetation samples were obtained and analyzed. Preliminary results indicate the amendments improved both establishment and growth; differences among amendment types and application rates were significant; and plant uptake of metals was not great enough to impact area wildlife. Additional results of the first growing season will be discussed.

On an approach to constructing compacta with different dimensions [formula omitted] and [formula omitted

In this paper we reveal common features in the constructions of some compacta X with dim X< ind X . To any regular T 1 -space X a class T(X) of regular T 1 -spaces is related. Elements of T(X) are called tailings of X. Two concrete types of tailings are described. For any compactum X with dim X= ind X>0 , these constructions allow to obtain compacta Y with dim Y= dim X and ind Y> dim X . At the end of the paper, using tailings, we present compacta with different dimensions dim and ind constructed by means of product formation starting from compacta with equal dim and ind .

Correlations for mine tailings consolidation parameters

ABSTRACT Because of the excessive time required for the determination of the compressibility and permeability of fine mine tailings, estimates of the volume required for the storage of such tailings are often based on very limited data. Correlations based on the index properties of mine tailings are presented that enable reliable estimates of the required parameters to be obtained rapidly. The index properties themselves may be determined within a week using small quantities of tailings. The correlations are based on data for disparate types of tailings and a variety of test methods. They are thus applicable to most mine tailings, but must be applied with caution to tailings in which chemical bonding may curtail consolidation or that contain significant quantities of relatively coarse particles or clays with fibrous particles.

Role of carbonates in mitigation of metal release from mining waste. Evidence from humidity cells tests

Leaching of two contrasting types of sulphidic tailings in humidity cells has been performed. The release of heavy metals and the oxidation rate have been studied. Tailings from the Laver mine contain a few percent sulphides and lack carbonates, whereas tailings from the Stekenjokk mine are both sulphide- and carbonate-rich. The results showed that in the leachates from the Laver samples, the metal concentrations increased and pH decreased with time, indicating an increased oxidation rate. In the Stekenjokk samples, pH remained high during the experiment, thereby keeping the metal concentrations low in the leachates. The oxidation rate also decreased with time, probably due to Fe-hydroxide coatings on sulphide surfaces. The results show that addition of carbonates and the maintenance of a high pH not only reduce the solubility of heavy metals, but also decrease the oxidation rate of sulphides.

Strengthening of Solidified Dilute Tailings Slurry

Tailings produced during mineral processing contain up to 75% or more water and are pumped into settling ponds for disposal. They often become a pollution source due to acid generation. While tailings have been used in underground backfill, the use is very limited at present. This paper presents research results on direct solidification and strengthening of the dilute tailings slurry without dewatering. Two types of tailings were tested at water/binder ratios of up to 4.5 using a special high-water binder. Adequate strength was achieved by solidifying the tailings as is. To further improve the strength, sands and fly ash were used as reinforcement materials or partial replacement of the binder. For oil sands tailings, the 3-day strength was increased by up to 114% with 10–15% additives. For hard rock tailings, up to 30% strength gain was achieved with 15% fly ash addition, and the strength was increased by up to 36% at 10% binder replacement and no strength reduction was observed at 20–25% replacement. These results indicate that higher strength can be achieved with the proper amount of additives and that the backfill process can be simplified and the operation cost reduced.

Migration of acidic groundwater seepage from uranium-tailings impoundments, 1. Field study and conceptual hydrogeochemical model

In this first paper of a series, the results of a study at a non-operational tailings site are presented and are used to construct a general conceptual model for seepage migration from uranium-tailings impoundments. Many parts of the model are applicable to other types of tailings and to acid drainage in general. At the field site, the impoundment lies over a portion of a glaciofluvial sand aquifer. Tailings seepage drains downward into the aquifer and then migrates laterally away. Results of the field study indicate the seepage can be divided into three geochemical zones: (1) the inner core, which is essentially unaltered, acidic seepage from the tailings; (2) the neutralization zone, in which inner-core water is neutralized and aqueous concentrations decrease significantly; and (3) the outer zone, which contains both neutralized water from the neutralization zone and pH-neutral process water from the uranium milling operation. Yearly comparisons from 1979 to 1984 indicate the neutralization zone and inner core are migrating downgradient at a rate of about 1 meter/year, which is about 1/440 of the groundwater velocity. The mechanisms that produce the retardation and the decreases in aqueous concentrations are part of the conceptual model. The main features of the conceptual model are solid-liquid interactions, particularly mineral precipitation-dissolution, and buffering effects of dominant aqueous species. The important minerals undergoing precipitation-dissolution are the calcite-siderite solid solution, gypsum, Al-OH minerals, and Fe-OH minerals. “Cell and streamtube” calculations are used to evaluate the general trends in aqueous concentrations and to assist in explaining observed migration rates. Co-precipitation with the above minerals apparently accounts for decreases in other major, minor, and metal solutes. Because of the large amount of mineral precipitation and co-precipitation, variations in 2H and 18O were observed over a flow distance of several meters, while 13C remained essentially constant.

Water leaching characteristics of uranium tailings from Ontario and Northern Saskatchewan

Column leaching tests are used to compare the leaching characteristics of several types of uranium tailings. The leaching characteristics of gypsum and radium-226 from Elliot Lake uranium tailings, as influenced by the methods employed in obtaining the tailings samples, the manner in which the tailings are loaded into lysimeters, and the aerobic/anaerobic conditions of the leach tests, are investigated. The purpose of this study is to obtain information on the release of environmental pollutants from uranium tailings in a shorter period of time than can be obtained by hydrogeological methods. The leaching characteristics of gypsum and radium-226 from leach residues derived from two laboratory tests on Saskatchewan uranium ores are compared to those of Elliot Lake tailings. Washing the tailings with potassium chloride (2 M) solution prior to the leaching test, or incorporation of peat moss and/or limestone in the column leaching tests greatly decreases the concentrations of radium-226 in the effluents of the column leaching tests.

Analyses of Flow Failures of Mine Tailings Dams

A characteristic common to most tailings dam failures is that the mine tailings tend to liquefy and flow over substantial distances, with potential for extensive damage to property and life. In order to be able to assess the potential for damage in case of such failure, it is necessary to be able to predict the characteristics of the flow and the possible extent of flood movement. This paper presents analytical procedures for making such evaluations. The behavior of tailings materials during flow is represented by a Bingham plastic rheological model in these analysis procedures. It is apparent from the analyses that the flow of phosphate tailings would be expected to be turbulent but flows for other types of tailings would be expected to be laminar. The procedures described are applicable for flow of tailings on horizontal and sloping planes and in prismatic valleys. The analyses can be performed using dimensionless charts in the case of flow on planes, and a computer program in the case of flow in prisma...

An improved sensitive assay for polonium-210 by use of a background-rejecting extractive liquid-scintillation method

A procedure is described for the determination of polonium-210 in various types of materials, including ores, mill tailings, and environmental samples, by a combined solvent-extraction liquid-scintillation spectrometry method. Concentration of polonium-210 and separation from interfering elements (such as iron) are accomplished by extraction from a 7M phosphoric acid-0.01M hydrochloric acid solution with 0.20M trioctylphosphine oxide solution (together with a scintillator) in toluene. The polonium-210 is determined by counting the 5.3-MeV alpha-radiation with a photon/ electron-rejecting alpha liquid-scintillation spectrometer. Extraction coefficients of over 1000 for polonium ensure quantitative recovery, and no other alpha-emitters in the decay chains of uranium-238, uranium-235 and thorium-232 are extracted. The results for several samples show the relative standard deviation to be ∼1.2%. A lower limit of detection of 0.0038 pCi is proposed, based on a counting time of 1000 min and an easily obtainable background of 0.01 cpm for the alpha peak.

Flow slides and the undrained brittleness index of some mine tailings

This paper discusses material parameters related to flow slides in saturated mine tailings embankments. Several studies of tailings embankment failures indicated that the failures took place very quickly and were characterized by extensive toe disturbance - both features typify flow slides in granular soils which are associated with large pore pressures and reduced (residual) shear strength. The brittleness index proposed by Bishop (1967, 1973) has been shown to relate postrupture behaviour of slopes to the peak and residual strength parameters of soils. In this study the undrained brittleness index was determined from stress-controlled isotropically consolidated undrained triaxial tests on tailings from three mining operations which produced garnet, iron ore and zinc. Test variables that influenced the brittleness index and thus peak and residual shear parameters included varying initial (before consolidation) void ratio, i.e., as placed relative density, and consolidation pressure. It was found that the initial void ratio was the most important parameter governing the undrained brittleness index. At a given initial void ratio the brittleness index generally increased with increasing consolidation pressures but the magnitude of this effect varied with the type of tailings. For the three types of tailings tested, it was found that when the initial dry unit weight was less than 70–75% of the maximum dry unit weight obtained from the modified Proctor test (ASTM D-1557), the undrained brittleness index was greater than 50% and further reduction in the initial dry unit weight had little effect on the index. However, the index decreased sharply to zero for all tailings over the range of consolidation pressures used when the initial percent dry unit weight increased from 75% to about 80%. This indicates that for the tailings tested and over the range of variables (initial unit weight and consolidation pressure) considered, the possibility of a flow slide due to a static load would be precluded if the initial compaction exceeded 80% of maximum.