Fresh water and acid sensitivity of authigenic clays in sandstone reservoirs

Authigenic illite-smectite and chlorite in reservoir sandstones from several Pacific rim sedimentary basins in Australia and New Zealand have been examined using an Electroscan Environmental Scanning Electron Microscope (ESEM) before, during, and after treatment with fresh water and HCl, respectively. These dynamic experiments are possible in the ESEM because, unlike conventional SEMs that require a high vacuum in the sample chamber (10-6 torr), the ESEM will operate at high pressures up to 20 torr. This means that materials and processes can be examined at high magnifications in their natural states, wet or dry, and over a range of temperatures (-20 to 1000 degrees C) and pressures. Sandstones containing the illite-smectite (60-70% illite interlayers) were flushed with fresh water for periods of up to 12 hours. Close examination of the same illite-smectite lines or filled pores, both before and after freshwater treatments, showed that the morphology of the illite-smectite was not changed by prolonged freshwater treatment. Chlorite-bearing sandstones (Fe-rich chlorite) were reacted with 1M to 10M HCl at temperatures of up to 80 degrees C and for periods of up to 48 hours. Before treatment the chlorites showed typically platy morphologies. After HCl treatment the chlorite grains were coated with an amorphous gel composed of Ca, Cl, and possibly amorphous Si, as determined by EDS analyses on the freshly treated rock surface. Brief washing in water removed this surface coating and revealed apparently unchanged chlorite showing no signs of dissolution or acid attack. However, although the chlorite showed no morphological changes, elemental analysis only detected silicon and oxygen.

Synthesis and characterisation of organo-beidellite

Today, there are growing concerns about the presence of environmental pollutants in many parts of the world. In particular, a lot of attention has been drawn to the levels of water and soil contaminants (de Paiva et al., 2008). The majority of these contaminants consist of NOCs (non-ionic organic compounds) and can enter our waterways through industrial activities, mining operations, crop and animal production, waste disposal and accidental leakage (de Paiva et al., 2008; Park et al., 2011). Therefore, there is an increased interest in the synthesis of new materials that can be used to remove potentially carcinogenic and toxic water contaminants. Smectite type organoclays are widely used in numerous applications, such as sorbent agents for environmental remediation, due to their unique properties (Jiunn-Fwu et al., 1990; Sheng et al., 1996; Zhou et al., 2007; Bektas et al., 2011; Park et al., 2011). This investigation focuses on beidellite (SBId-1), which belongs to the smectite clay family. Their properties include high cation exchange capacity (CEC), swelling properties, porous, high surface area and consequential strong adsorption/absorption capacity (Xi et al., 2007). However, swelling clays in general are not an effective sorbent agent in nature due to their hydrophilic properties. The hydrophilic properties of the clay can be changed to organophilic by intercalating a cationic surfactant. Many applications of organoclays are strongly dependent on their structural properties and hence, a better understanding of the configuration and structural change of organoclay is crucial. Organoclays were synthesised through ion exchange of 21CODTMA (MW: 392.5 g mol-1) and characterised using XRD and FTIR spectroscopy. This study investigates the structural and conformational changes of beidellite intercalated with octadecyltrimethylammonium bromide.

Concepts, water and reflections on practice

This paper discusses the nature of the conceptual structure in art practice, by example. It draws on insights gained from a practice based research (PBR) approach to making art. The PBR methods used include Reflective Practice and are briefly described. They have informed an understanding of the conceptual structure as an instance of problem framing. This is demonstrated by two creative examples, taken from two interactive artworks. These were informed by an evolving conceptual structure concerned with water.

Development of lightweight concrete with high resistance to water and chloride-ion penetration

This paper presents an experimental study to evaluate the influence of coarse lightweight aggregate (LWA), fine LWA and the quality of the paste matrix on water absorption and permeability, and resistance to chloride-ion penetration in concrete. The results indicate that incorporation of pre-soaked coarse LWA in concrete increases water sorptivity and permeability slightly compared to normal weight concrete (NWC) of similar water-to-cementitious materials ratio (w/cm). Furthermore, resistance of the sand lightweight concrete (LWC) to water permeability and chloride-ion penetration decreases with an increase in porosity of the coarse LWA. The use of fine LWA including a crushed fraction <1.18 mm reduced resistance of the all-LWC to water and chloride-ion penetration compared with the sand-LWC which has the same coarse LWA. Overall, the quality of the paste matrix was dominant in controlling the transport properties of the concrete, regardless of porosity of the aggregates used. With low w/cm and silica fume, low unit weight LWC (_1300 kg/m3) was produced with a higher resistance to water and chloride-ion penetration compared with NWC and LWC of higher unit weights.

Water and chloride ion penetration resistance of highstrength ultra lightweight cement composite

Durability is a significant issue to focus on for newly developed structural lightweight cement composite (ULCC). This paper presents an experimental study to evaluate the resistance of ULCC to water and chloride ion penetration. Chloride penetrability and sorptivity were evaluated for ULCC (unit weight about 1450 kg/m3) and compared with those of a normal weight concrete (NWC), a lightweight aggregate concrete (LWC), and an ultra lightweight composite with proprietary cementitious binder (DB) (unit weight about 1450 kg/m3) at similar compressive strength of about 60 MPa. Rapid chloride penetrability test, rapid migration test, water absorption (sorptivity) test, and water permeability test were conducted on these mixtures. Results indicate that ULCC and DB had comparable performance. Compared with control LWC and NWC at similar strength level, the ULCC and DB mixtures had higher resistance to chloride ion penetration, lower water absorption and virtually impermeable to water penetration.

Development of lightweight aggregate concrete with high resistance to water and chloride-ion penetration

This paper presents an experimental study to evaluate the effect of coarse and fine LWA in concrete on its water absorption and permeability, and resistance to chloride-ion penetration. In additions, LWC with lower unit weight of about 1300 kg/m3 but high resistance to water and chloride-ion penetration was developed and evaluated. The results indicate that the incorporation of coarse LWA in concrete increases water sorptivity and permeability slightly compared to NWC of similar w/c. The resistance of the sand-LWC to chloride-ion penetration depends on porosity of the coarse LWA. Fine LWA has more influence on the transport proper-ties of concrete than coarse LWA. Use of lightweight crushed sand <1.18 mm reduced the resistance of the LWC to water and chloride-ion penetration to some extent. With low w/cm and silica fume, low unit weight LWC (~1300 kg/m3) was produced with higher resistance to water and chloride ion penetration compared with concretes of higher unit weights.

Isolation of nontuberculous mycobacteria (NTM) from household water and shower aerosols in patients with pulmonary disease caused by NTM

It has been postulated that susceptible individuals may acquire infection with nontuberculous mycobacteria (NTM) from water and aerosol exposure. This study examined household water and shower aerosols of patients with NTM pulmonary disease. The mycobacteria isolated from clinical samples from 20 patients included M. avium (5 patients), M. intracellulare (12 patients), M. abscessus (7 patients), M. gordonae (1 patient), M. lentiflavum (1 patient), M. fortuitum (1 patient), M. peregrinum (1 patient), M. chelonae (1 patient), M. triplex (1 patient), and M. kansasii (1 patient). One-liter water samples and swabs were collected from all taps, and swimming pools or rainwater tanks. Shower aerosols were sampled using Andersen six-stage cascade impactors. For a subgroup of patients, real-time PCR was performed and high-resolution melt profiles were compared to those of ATCC control strains. Pathogenic mycobacteria were isolated from 19 homes. Species identified in the home matched that found in the patient in seven (35%) cases: M. abscessus (3 cases), M. avium (1 case), M. gordonae (1 case), M. lentiflavum (1 case), and M. kansasii (1 case). In an additional patient with M. abscessus infection, this species was isolated from potable water supplying her home. NTM grown from aerosols included M. abscessus (3 homes), M. gordonae (2 homes), M. kansasii (1 home), M. fortuitum complex (4 homes), M. mucogenicum (1 home), and M. wolinskyi (1 home). NTM causing human disease can be isolated from household water and aerosols. The evidence appears strongest for M. avium, M. kansasii, M. lentiflavum, and M. abscessus. Despite a predominance of disease due to M. intracellulare, we found no evidence for acquisition of infection from household water for this species.

IODP Expedition 339 in the Gulf of Cadiz and off West Iberia : decoding the environmental significance of the Mediterranean outflow water and its global influence

IODP Expedition 339 drilled five sites in the Gulf of Cadiz and two off the west Iberian margin (November 2011 to January 2012), and recovered 5.5 km of sediment cores with an average recovery of 86.4%. The Gulf of Cadiz was targeted for drilling as a key location for the investigation of Mediterranean outflow water (MOW) through the Gibraltar Gateway and its influence on global circulation and climate. It is also a prime area for understanding the effects of tectonic activity on evolution of the Gibraltar Gateway and on margin sedimentation. We penetrated into the Miocene at two different sites and established a strong signal of MOW in the sedimentary record of the Gulf of Cadiz, following the opening of the Gibraltar Gateway. Preliminary results show the initiation of contourite deposition at 4.2–4.5 Ma, although subsequent research will establish whether this dates the onset of MOW. The Pliocene succession, penetrated at four sites, shows low bottom current activity linked with a weak MOW. Significant widespread unconformities, present in all sites but with hiatuses of variable duration, are interpreted as a signal of intensified MOW, coupled with flow confinement. The Quaternary succession shows a much more pronounced phase of contourite drift development, with two periods of MOW intensification separated by a widespread unconformity. Following this, the final phase of drift evolution established the contourite depositional system (CDS) architecture we see today. There is a significant climate control on this evolution of MOW and bottom-current activity. However, from the closure of the Atlantic–Mediterranean gateways in Spain and Morocco just over 6 Ma and the opening of the Gibraltar Gateway at 5.3 Ma, there has been an even stronger tectonic control on margin development, downslope sediment transport and contourite drift evolution. The Gulf of Cadiz is the world's premier contourite laboratory and thus presents an ideal testing ground for the contourite paradigm. Further study of these contourites will allow us to resolve outstanding issues related to depositional processes, drift budgets, and recognition of fossil contourites in the ancient record on shore. The expedition also verified an enormous quantity and extensive distribution of contourite sands that are clean and well sorted. These represent a relatively untapped and important exploration target for potential oil and gas reservoirs.

Systems modelling of mine water and energy tradeoffs

In the coming decades, the mining industry faces the dual challenge of lowering both its water and energy use. This presents a difficulty since technological advances that decrease the use of one can increase the use of the other. Historically, energy and water use have been modelled independently, making it difficult to evaluate the true costs and benefits from water and energy improvements. This paper presents a hierarchical systems model that is able to represent interconnected water and energy use at a whole of site scale. In order to explore the links between water and energy four technologies advancements have been modelled: use of dust suppression additives, the adoption of thickened tailings, the transition to dry processing and the incorporation of a treatment plant. The results show a synergy between decreased water and energy use for dust suppression additives, but a trade-off for the others.

Regional trade-offs between mine water and energy use : a water treatment case study

The mining industry faces concurrent pressures of reducing water use, energy consumption and greenhouse gas (GHG) emissions in coming years. However, the interactions between water and energy use, as well as GHG e missions have largely been neglected in modelling studies to date. In addition, investigations tend to focus on the unit operation scale, with little consideration of whole-of-site or regional scale effects. This paper presents an application of a hierarchical systems model (HSM) developed to represent water, energy and GHG emissions fluxes at scales ranging from the unit operation, to the site level, to the regional level. The model allows for the linkages between water use, energy use and GHG emissions to be examined in a fl exible and intuitive way, so that mine sites can predict energy and emissions impacts of water use reduction schemes and vice versa. This paper examines whether this approach can also be applied to the regional scale with multiple mine sites. The model is used to conduct a case study of several coal mines in the Bowen Basin, Australia, to compare the utility of centralised and decentralised mine water treatment schemes. The case study takes into account geographical factors (such as water pumping distances and elevations), economic factors (such as capital and operating cost curves for desalination treatment plants) and regional factors (such as regionally varying climates and associated variance in mine water volumes and quality). The case study results indicate that treatment of saline mine water incurs a trade-off between water and energy use in all cases. However, significant cost differences between centralised and decentralised schemes can be observed in a simple economic analysis. Further research will examine the possibility for deriving model up-scaling algorithms to reduce computational requirements.