Academic literature on the topic 'Tailings retreatment'

Abstract Froth separation is one of the new methods of flotation process in mineral treatment. This method allows a substantial increase in the size upper limit of separated grains. The contribution deals with the verification of the possibility of using the froth separation for retreatment of flotation tailings. For laboratory research samples of flotation tailings from the Paskov Mine treatment complex were used. The results confirmed the ability of froth separation to convert coarse coal grains into a concentrate. Grains with a grain size of 0.5 mm were successfully reflotated.

Rough processing of iron ore employs dry methods which means that equipment is tuned to process large particles, but fine magnetic material less than a few tenths of a millimeter in size is not separated as efficiently. The relevance of this study is determined by the fact that dry beneficiation waste contains recoverable iron-bearing magnetite of commercial value. Commercial justification of waste beneficiation is associated with mining and grinding costs that are already included in the prime cost of the commercial concentrate. The future of tailings retreatment prospects depends on technology and efficiency of the employed equipment, the development of which is the subject of this paper. At first stage, fine iron is recovered by air sizing, with pitched curtain air classifiers embedding simple design and high performance. Powder materials were magnetically separated by a manufactured drum-type separator in which, to increase the separation efficiency, the process was performed at increased drum rotation speeds using Nd-Fe-B magnets and a drum made of electrically non-conductive materials. The separator performance was determined for various rotation speeds of the drum. Research has proven that a multi-stage magnetic separation with a consequent increase in drum rpm is reasonable. A new cascade separator was manufactured and tested for this purpose. It is shown that iron-containing ore tailings beneficiation is optimal without any additional grinding.

SYNOPSIS The reprocessing of tailings resources to extract gold on an industrial scale has become common practice. While these projects are common in the Witwatersrand basin, similar low-technology processes are not operational in smaller goldfields. This study explores the possibility of reclaiming the tailings dump of the Louis Moore Mine in the Giyani Greenstone Belt, investigates potential hazards to communities in the vicinity, and identifies mitigation strategies. Auger samples were taken from the Louis Moore tailings at depths of up to 5 m. Aqua regia leach analyses show Au concentrations of up to 1 g/t. Inferred estimations based on ordinary kriging (OK) and inverse distance weighted (IDW) methods put the residual Au resource in the Louis Moore tailings dump at 0.20 t. Reworking the tailings is viable, although a potential environmental risk exists in the form of elevated arsenic concentrations. Further exploration is required to determine the mineralogical associations of Au and As. Tailings reworking would assist in raising funds for mine rehabilitation. The secondary tailings could potentially be repurposed, which would provide employment and facilitate community development, as well as deliver environmental benefits. Keywords: Louis Moore, tailings, gold, safety and health.

Abstract In recent times, the potential beneficial uses of abandoned mine sites have been recognised and acted upon through the retreatment of tailings in order to win minerals of interest still available in economically viable concentrations. The most notable benefit (although not usually factored in financially) is that, once the tailings have been removed, the land has a greater potential to be developed further. The main aim of this study was to investigate the contents of copper and potentially harmful elements in the tailings of the Musina mine, an abandoned Cu mine in the northern Limpopo Province, in order to assess environmental hazards and to provide a first estimate of the feasibility of future economic rehabilitation. The concept of reclaiming was here seen in a broad way and ranged from the reworking of tailings or other residues to residential and/or recreational use. To quantify the potential economic importance and impacts of the metal content of the tailings, geochemical analysis of samples from auger holes and resource modelling were employed. Neutral to slightly basic pH values and very low concentrations of arsenic and lead showed that acid drainage and toxic groundwater contamination (apart from Cu itself) would not be a concern. Three-dimensional (3D) and two-dimensional (2D) models were applied to estimate the resource potential of the tailings dump. The models revealed that residual Cu in the Musina mine tailings is currently at 8555 tonnes. Accordingly, going forward, we recommend a formalised geometallurgical study to assess the economic feasibility of extracting Cu, with a view to reworking the copper tailings dump. It is very important that this tailings dump be mined in future, in order to extract all Cu and ensure that the sterilised land (up to 95 ha) can be used for other purposes.

Tailings dam retreatment can be considered as a profitable alternative when tailings contain relatively high metal contents. Moreover, because of low exploration, mining, processing and closure costs, and the recent rise in copper prices, retreatment may generate positive cash flow. Meanwhile revenue from metal extraction can offset rehabilitation cost leading to an improved long-term liability performance. A systematic approach and an Excel spreadsheet model are developed to evaluate economic profits, environmental and social benefits derived from retreatment, and to simulate human decision-making processes. Fuzzy logic and fuzzy-neural equations were employed in the model to deal with imperious and linguistic inputs, and to simulate human’s decision-making process. By user questionnaire and surveys, the model receives inputs data, which will be processed through four different modules to generate final outputs. Economic and Design Module completes conceptual processing flowsheet design, cost estimate, and economic analysis of base case and retreatment project. A Disposal and Reclamation Module is designed to select re-processed tailings disposal and reclamation methods, estimate cost and evaluate the environmental performance. A Risk Assessment Module is aimed at environmental and social risks evaluation of current tailings site. After receiving all the criteria on economic, environmental and social performance improvement, a Decision-Making Module is developed to provide user a recommendation. Generally speaking, this model is able to conceptually design activities from mining to reclamation; evaluate economic, environmental and social benefits; assist multi-criteria decision-making. Four hypothetical cases with different conditions have been processed to validate and verify the retreatment model. As indicated by model running results, the tailing retreatment module is an effective tool to assist in decision making. In addition, the system is working properly and efficiently on given inputs over a range and combination of values.

Inadequate rehabilitation over the life of the historic Mount Morgan mine (1882-1981), and since tailings retreatment ceased in 1990, has led to the continued impact of acid mine drainage on the Dee River.

The water quality along the Dee River, for 18 km downstream of the mine site to its junction with Fletcher Creek, is characterised by low pH, consistently below 3.5 (Howse, 2003). The concentration of metals in surface water is generally elevated adjacent to the mine (Al 191 mg/L, Cd 0.06 mg/L, Cu 16.7 mg/L, Pb 0.10 mg/L and Zn 6.4 mg/L) and is acceptable for irrigation/stock water downstream of Fletcher Creek (Al <0.5 mg/L, Cd <0.005 mg/L, Cu <0.05 mg/L, Pb <0.05 mg/L and Zn <0.05 mg/L). 

This study investigated the chemical impacts of acid mine drainage from the mine; in particular the concentration of metals was measured in surface water, groundwater, sediment, soil and agricultural produce.

The Dee River Research Project was initiated by the Wowan Dululu Landcare Group (Central Queensland) - a community group with common interests in sustainable farming, grazing and other environmental and community issues. Determining whether acid mine drainage had impacted on agricultural produce was of particular interest to the rural community of Wowan and Dululu.

The metal concentrations in lucerne, lucerne hay and citrus suggested that acid mine drainage from the Mount Morgan mine did not significantly impact on the quality of these produce. The concentrations of Cu, Fe, Mn, Pb, Zn and S in lucerne hay were acceptable for dietary intake by cattle. The concentrations of Cd, Cu, Pb and Zn in all mandarin samples were below the maximum permitted concentration set in the Australian Food Standards Code. 

Four acid flow events and fish kills occurred in the Dee River between November 2000 and February 2001 as a result of acid mine drainage from the historic Mount Morgan mine. Measurements of pH along the Dee River clearly demonstrated the movement of a slug of acidic water down the river during each of the four flow events (pH 3.0 at 3 km (Kenbula weir), pH 4.8 at 60 km and pH 6.1 at 80 km downstream of the mine site). Laboratory analysis of water samples indicated Al, Cu and Zn concentration orders of magnitude above ANZECC guidelines. Fish kills occurred with each flow event and killed an estimated total of 26,000 fish.

From November 2000 to February 2001 over 33,500 ML of acidic water (pH <5) flowed along the Dee River and transported over 50 tonnes of Al, 5 tonnes of Cu, 3.5 tonnes of Zn and over 1,500 tonnes of SO4.

Sediments downstream of the Mount Morgan mine site were contaminated with Cd, and Zn and particularly Cu where concentrations of 1,700 mg/kg were 25 times greater than the ANZECC (2000a) interim sediment quality guidelines. Soil on the Dee River floodplain (60 km downstream of the mine) was contaminated with Cu; the maximum concentration of 2,510 mg/kg exceeded the NEPC (1999) Ecological Investigation Level (100 mg/kg) and Health Investigation Level (1,000 mg/kg).

A large proportion (> 50%) of Cu, Cd, Mn and Zn in sediment and soil was found to be associated with the most mobile fractions; metal concentrations in these fractions alone mostly exceeded the ANZECC (2000a) interim sediment quality guidelines/ NEPC (1999) guidelines. The significance of these results is discussed with respect to potential bioavailability of metals to cattle. 

Peak metal concentration in groundwater coincided with high metal levels of acid surface water of the Dee River at two sites (6 km and 38 km downstream of the mine site). Results presented herein support the premise that metal -rich water originating from the Mt Morgan mine site could infiltrate groundwater, particularly during acid flow events in the Dee River when preceding groundwater levels are low. 

The fate of the metals from the Mount Morgan mine site was inferred from the results and the contaminants pathway depicted in a conceptual model.