Abstract: The common sulfide mineral pyrite is abundant throughout sedimentary uranium systems at Pepegoona, Pepegoona West and Pannikan, Lake Eyre Basin, South Australia. Combined chemical, isotopic and microstructural analysis of pyrite indicates variation in fluid composition, sulfur source and precipitation conditions during a protracted mineralization event. The results show the significant role played by pyrite as a metal scavenger and monitor of fluid changes in low-temperature hydrothermal systems. In-situ micrometer-scale sulfur isotope analyses of pyrite demonstrated broad-scale isotopic heterogeneity (δ34S=−43.9 to +32.4‰VCDT), indicative of complex, multi-faceted pyrite evolution, and sulfur derived from more than a single source. Preserved textures support this assertion and indicate a genetic model involving more than one phase of pyrite formation. Authigenic pyrite underwent prolonged evolution and recrystallization, evidenced by a genetic relationship between archetypal framboidal aggregates and pyrite euhedra. Secondary hydrothermal pyrite commonly displays hyper-enrichment of several trace elements (Mn, Co, Ni, As, Se, Mo, Sb, W and Tl) in ore-bearing horizons. Hydrothermal fluids of magmatic and meteoric origins supplied metals to the system but the geochemical signature of pyrite suggests a dominantly granitic source and also the influence of mafic rock types. Irregular variation in δ34S, coupled with oscillatory trace element zonation in secondary pyrite, is interpreted in terms of continuous variations in fluid composition and cycles of diagenetic recrystallization. A late-stage oxidizing fluid may have mobilized selenium from pre-existing pyrite. Subsequent restoration of reduced conditions within the aquifer caused ongoing pyrite re-crystallization and precipitation of selenium as native selenium. These results provide the first qualitative constraints on the formation mechanisms of the uranium deposits at Beverley North. Insights into depositional conditions and sources of both sulfide and uranium mineralization and an improved understanding of pyrite geochemistry can also underpin an effective vector for uranium exploration at Beverley North and other sedimentary systems of the Lake Eyre Basin, as well as in comparable geological environments elsewhere.

Abstract: This study investigated the process of in situ leaching (ISL) method of uranium mining, and the removal of solid particles from the leaching solution. Investigations were carried out for 4months. The content of firm suspensions in the productive solutions arriving from the well field was up to standard of 3–5mg/l. After keeping in a settler of productive solutions within one hour concentration of suspensions decreases to 2–2.5mg/l. To increase the life of the wells requires more fine purification of the ISL solutions. The best results can be obtained but using filtration. Bag filters were used in experiments carried out at the extraction site. All samples of polypropylene bag filter was produced by the Tamfelt Corporation. The best results were obtained for fabrics S-51M03-L2K4 (pore size 3μm). After three month of trials following indicators of wells work were fixed: on the trial cell decrease in intake capacity did not occur; on the other cells of well field injectability of holes for the same period of time decreased for 15–40%. The results illustrated the high efficiency of this method, which allows injection wells to reach a constant intake capacity, making it possible for technological cells to achieve a constant productivity and balance. Purification of solutions allows to reduce acidulation term of new technological cells from 3–4 to 1.5–2months.

Abstract: Elevated groundwater nitrate levels are common in drylands, often in excess of WHO guidelines, with concern for human and animal health. In light of recent attempts to identify nitrate sources in the Kalahari this paper presents the first unsaturated zone (USZ) nitrate profiles and recharge rate estimates for the important transboundary Stampriet Basin, alongside the first rainfall chemistry records. Elevated subsurface nitrate reaches 100–250 and 250–525 mg/L NO3–N, with NO3–N/Cl of 4–12, indicating input above evapotranspiration. Chloride mass balance recharge rates range from 4 to 27 mm/y, indicating a vertical movement of these nitrate pulses toward the water table over multi-decadal timescales. These profiles are sampled from dune crests, away from high concentrations of animals and without termite mounds. Given low-density animal grazing is unlikely to contribute consistent spot-scale nitrate over decades, these profiles give an initial estimate of naturally-produced concentrations. This insight is important for the management of the Stampriet Basin and wider Kalahari groundwater. This study expands our knowledge about elevated nitrate in dryland USZs, demonstrating that it can occur as pulses, probably in response to transient vegetation cover and that it is not limited to long-residence time USZs with very limited downward moisture flux (recharge).

Abstract: Engineering heritage refers to a broad variety of items of social, economic, aesthetic or historic relevance, including roads, dams, buildings and supply networks. Due to their utilitarian nature, their heritage value is often overlooked. This occurs even with those infrastructures that have played an essential role in underpinning the daily existence of entire civilizations. Underground water-supply networks provide an excellent example. Although there are exceptions, water networks tend to be functional in design, rather than monumental. Moreover, they present intricate linear layouts that often span several kilometres. This means they are costly to maintain once their operational life is over, and that they are prone to abandonment and destruction. Devising a priori protection strategies is important to preserve these valuable cultural assets. The following pages present a method to map linear structures based on archive records and sparse material remains. The method is illustrated through its application to the Amaniel qanat, a water-supply gallery built in Madrid, Spain, in the early 17th Century. An appraisal of the known remains was carried out first, leading to an inventory of galleries, shafts, shaft caps and deposits. This was followed by a thorough survey of over one thousand handwritten manuscripts, including physical descriptions of the aqueduct, budget accounts or water metering campaigns, among other documents. Known remains and written evidence were matched against original and auxiliary maps to reconstruct the itinerary of the aqueduct. This led to the identification of sectors where it is still possible to find remains in good condition. Thus, a priori mapping is advocated a valuable technique to locate and preserve these remains, as well as to devise non-invasive surveys and establish heritage protection zones.