bluuebunny/crossref_metadata_2025 huggingface dataset:
Public geoscience to reduce exploration risk: new methods to characterize the basement beneath geological cover and to address community engagement in the Cariboo-Chilcotin region of British Columbia1This article introduces a series of papers published in this Special Issue on the theme of New insights in Cordilleran Intermontane geoscience: reducing exploration risk in the mountain pine beetle-affected area, British Columbia. James Haggart is the Special Issue guest editor.2Geological Survey of Canada Contribution 20100476.
Authors: Haggart James W. , Harris Josephine M. , Hutton Christine A.
Published: July 2011

Mineral and petroleum exploration in the Cariboo-Chilcotin region of British Columbia is hampered by widespread and extensive cover of Pleistocene glacial deposits and Tertiary volcanic successions. Seeing through this geological cover is critical to reducing exploration risk and enhancing exploration activity. Also critical to exploration is effective community engagement, hopefully resulting in endorsement and support for exploration initiatives. The forests in the Cariboo-Chilcotin region have been extensively destroyed by an infestation of the mountain pine beetle, Dendroctonus ponderosae , disrupting established communities and greatly affecting economic activity in the region. Governments of all levels recognized that geological exploration activity could provide a ready and appreciable stimulus to economic activity, but only if local communities endorsed such programs. Relatively little oil and gas exploration and research has taken place in the region, and its effects have been poorly understood locally. Consequently, an extended effort was undertaken to establish an integrated geoscience program for the Cariboo-Chilcotin region, focused on mineral and petroleum exploration-related research and coupled with engagement with local communities to inform them of exploration benefits and risks. This Introduction to the “Mountain Pine Beetle” Special Issue of Canadian Journal of Earth Sciences provides a brief overview of the scientific papers included in the issue and also a review of the community engagement process that was undertaken to establish working relationships with First Nations and other communities in the region.
Lithostratigraphic and tectonic framework of Jurassic and Cretaceous Intermontane sedimentary basins of south-central British Columbia1This article is one of a series of papers published in this Special Issue on the theme of New insights in Cordilleran Intermontane geoscience: reducing exploration risk in the mountain pine beetle-affected area, British Columbia.
Authors: Riddell Janet
Published: July 2011

The south-central Intermontane belt of British Columbia has a complex architecture comprising late Paleozoic to Mesozoic volcanic and plutonic arc magmatic suites, marine and nonmarine clastic basins, high-grade metamorphic complexes, and accretionary rocks. Jurassic and Cretaceous clastic basins within this framework contain stratigraphy with hydrocarbon potential. The geology is complicated by Cretaceous to Eocene deformation, dismemberment, and dislocation. The Eocene to Neogene history of the southern Intermontane belt is dominated by non-arc volcanism, followed by Pleistocene to Recent glaciation. The volcanic and glacial cover makes this a difficult region to explore for resources. Much recent work has involved re-evaluating the challenges that the overlying volcanic cover has historically presented to geophysical imaging of the sedimentary rocks in this region in light of technological advances in geophysical data collection and analysis. This paper summarizes the lithological and stratigraphic framework of the region, with emphasis on description of the sedimentary units that have been the targets of hydrocarbon exploration.
Displacement-based seismic design of regular reinforced concrete shear wall buildings
Authors: Humar JagMohan , Fazileh Farrokh , Ghorbanie-Asl Mohammad , Pina Freddy E.
Published: July 2011

A displacement based method for the seismic design of reinforced concrete shear wall buildings of regular shape is presented. For preliminary design, approximate estimates of the yield and ultimate displacements are obtained, the former from simple empirical relations, and the latter to keep the ductility demand within ductility capacity and to limit the maximum storey drift to that specified by the codes. For a multi-storey building, the structure is converted to an equivalent single-degree-of-freedom system using an assumed deformation shape that is representative of the first mode. The required base shear strength of the system is determined from the inelastic demand spectrum corresponding to the ductility demand. In subsequent iterations a pushover analysis for the force distribution based on the first mode is used to obtain better estimates of yield and ultimate displacements taking into account stability under P–Δ effect. A multi-mode pushover analysis is carried out to find more accurate estimates of the shear demand.
Comparative testing of numerical models of river ice jams
Authors: Carson Rick , Beltaos Spyros , Groeneveld Joe , Healy Dan , She Yuntong , Malenchak Jarrod , Morris Mike , Saucet Jean-Philippe , Kolerski Tomasz , Shen Hung Tao
Published: July 2011

Ice processes in general, and ice jams in particular, play a dominant role in the hydrologic regime of Canadian rivers, often causing extreme floods and affecting the life cycle of many aquatic, terrestrial, and avian species. Various numerical models have been developed to help simulate the formation and consequences of these very dynamic and often destructive jam events. To test and compare the performance of existing models, a series of three tests have been devised and coordinated by a task force appointed by the Committee on River Ice Processes and the Environment (CRIPE). The results indicate that the overall performance of the models is good when calibration data are available, but considerably more varied when the models are applied in uncalibrated or “blind” mode. However, the diversity of results in the blind mode may be attributed more to the variations in perceptions of the physical processes by the users, as compared to the mechanics of the numerical computations.
Current status of factors leading to team performance of on-site construction professionals in Alberta building construction projects
Authors: Hewage Kasun N. , Gannoruwa Anupama , Ruwanpura Janaka Y.
Published: July 2011

A skill-measuring criterion or strategy can be used to optimize the scarce skilled labour force in the Canadian construction industry. The University of Calgary conducted an extensive study to assess the skill levels and team performance of field workers and managers in Alberta’s building construction projects. Over 150 workers and field managers were interviewed, surveyed with questionnaires and observed, to identify team efficiencies, skill levels, team spirit, and team perceptions of supervision. The average construction worker had over 15 years of field experience. Most of the workers were high school educated. More than 70% of the workers wanted to improve their career skills; however, internal and external opportunities were limited and (or) not promoted by the respective construction companies. A very few foremen had certified skills in administration, computer handling, planning, job management and work records. The research clearly noted the urgent need for training programs, for workers and field managers, to improve their present skill levels.
Application of water rights priority and natural priority orders to river and reservoir operation systems
Authors: Kim Tae Jin
Published: July 2011

Surface water rights in Texas are developed based on “Prior Appropriation Doctrine”. The Texas Water Availability Model, a computer-based simulation model based on water rights priority order, has been used for computing the amount of water supply and determining the amount of water available for a newly requested water right for the past several years. This study compares the water rights priority and natural priority orders by applying it to the largest sixteen reservoirs in the Brazos River Basin, Texas. The water supply reliability, reservoir storage frequency, and stream flows are analyzed corresponding to each priority orders. The natural priority order increases water supply reliability for most reservoirs about 1 to 2% and mean reservoir storage volume located in the upper basin than water rights priority order. The stream flows based on water rights priority order are more regulated than natural priority order by 3 and 5%. The composite priority order is more effective than each priority order in increasing the water supply reliability.
Spat production of the great scallop (Pecten maximus): a roller coaster1This review is part of a virtual symposium on current topics in aquaculture of marine fish and shellfish.
Authors: Andersen S. , Christophersen G. , Magnesen T.
Published: July 2011

The great scallop ( Pecten maximus (L., 1758)) has been of interest for aquaculture in Europe since the early 1970s. Since then, a large part of the research and development has focussed on reproduction and early life stages to support hatchery production of spat. Results from the last two decades show that production stability is lacking and have followed a roller-coaster trend. Production strategy varies, but in general, broodstock are collected from the wild and conditioned to gonad maturity sufficient for successful spawning. Natural reproduction cycle varies between populations, which is a challenge to hatcheries aiming at stable year-round production. Larval survival was for many years dependent on addition of antibiotics until a flow-through culture was established, and seasonal variation may be caused by variation in gamete or seawater quality. Settlement, metamorphosis, and spat growth depend on healthy larvae and appropriate culture environment. For efficient spat production, the use of land-based nurseries is promising. Results show that mean yield of spat from eggs is less than 1%. The review concludes that the gap between results obtained in hatchery production and in experiments shows a great potential for production increase.
Transcriptomics for understanding marine fish larval development1This review is part of a virtual symposium on current topics in aquaculture of marine fish and shellfish.
Authors: Mazurais D. , Darias M. , Zambonino-Infante J.L. , Cahu C.L.
Published: July 2011

The larval phase is a crucial period in the life of marine fish. During this phase, the organism will acquire the phenotype of an adult fish through the development of tissues and organs and the maturation of some of the principal physiological functions. Many biological processes (differentiation, cellular proliferation, growth, etc.) are regulated during this period. These regulations take place at different biological levels and particularly concern the expression of genes involved in larval ontogenesis processes. The development of bioinformatic resources (DNA or cDNA sequences) and molecular tools enabling high throughput gene expression analysis (microarrays) have allowed the transcriptome of marine fish species to be studied. In the present review, we summarize the main findings from transcriptomic investigations of development of marine fish larvae. Special attention is paid to investigations of transcriptomic patterns during postembryonic development and to the impact of environmental or nutritional factors on the transcriptome of marine fish larvae. Transcriptomic approaches will be especially useful in the future for investigating the effect of temperature and water acidification (or pH) on the development of different fish species in the context of global climate change.
STANDARD-FREE METHOD FOR LIVING PLANTS IN IN-AIR PIXE
Authors: SERA K. , GOTO S. , TAKAHASHI C. , SAITOH Y.
Published: July 2011

A standard-free method for living plants in in-air PIXE has been developed in order to clarify the mechanism of elemental transportation and movement in farm products. The components of the continuous X-rays originated from air and a backing film can be exactly subtracted using a blank spectrum after normalization by the yields of Ar K α X-rays. It is found by observing the yield of continuous X-rays with passage of time that water content is continuously decreasing during irradiation with a proton beam in a case of pinched leaves. In contrary, it is kept almost constant during irradiation for the living plants to which water is continuously provided through the roots. Stability of the yield of continuous X-rays is a required condition for a standard-free method, which makes use of the yield of continuous X-rays mainly emitted from water content. It is confirmed that potassium concentration shows no large position dependence on a leaf, and it keeps almost constant during irradiation, which also indicates that regular metabolism is going on. As potassium is always contained in all kinds of plants in large amount, it is designated as an index element. As a result, it is found that the potassium concentration obtained by the present standard-free method shows quite consistent values with those obtained by the internal-standard method. The present method is confirmed to be quite useful for investigating movement of not only toxic elements but also essential elements reflecting metabolism in plants.
MULTIBREATHER AND VORTEX BREATHER STABILITY IN KLEIN–GORDON LATTICES: EQUIVALENCE BETWEEN TWO DIFFERENT APPROACHES
Authors: CUEVAS J. , KOUKOULOYANNIS V. , KEVREKIDIS P. G. , ARCHILLA J. F. R.
Published: July 2011

In this work, we revisit the question of stability of multibreather configurations, i.e. discrete breathers with multiple excited sites at the anti-continuum limit of uncoupled oscillators. We present two methods that yield quantitative predictions about the Floquet multipliers of the linear stability analysis around such exponentially localized in space, time-periodic orbits, based on the Aubry band method and the MacKay effective Hamiltonian method, and prove that by making the suitable assumptions about the form of the bands in the Aubry band theory, their conclusions are equivalent. Subsequently, we showcase the usefulness of the methods through a series of case examples including one-dimensional multi-breathers, and two-dimensional vortex breathers in the case of a lattice of linearly coupled oscillators with the Morse potential and in that of the discrete ϕ4 model.
BIFURCATIONS FROM PLANAR TO THREE-DIMENSIONAL PERIODIC ORBITS IN THE RING PROBLEM OF N BODIES WITH RADIATING CENTRAL PRIMARY
Authors: KALVOURIDIS T. J. , HADJIFOTINOU K. G.
Published: July 2011

We consider the three-dimensional motion of a massless particle in a regular polygon formation of N primary bodies, one of which is located at the system's center of mass. Assuming that the central primary is a radiation source, we apply the simplified theory suggested by Radzievskii, in order to study the effect of radiation pressure in the three-dimensional dynamics of the system. We particularly study the evolution of the zero-velocity surfaces for various values of the radiation coefficient b0 and investigate also the cases with b0 > 1 (that is, radiation surpasses gravity) since for these cases, significant changes in the dynamics occur. We then locate numerically the onset of three-dimensional periodic motion from planar periodic motion by calculating the orbits' vertical critical stability. Many families of three-dimensional periodic motions are presented and the regions of the three-dimensional space where these motions take place, are determined. We subsequently investigate how the bifurcations from planar to three-dimensional periodic orbits are affected by the increase of the primary's radiation coefficient and how the overall dynamics of the system is affected by the value of the primaries' number N.
ORBITS IN A NON-KERR DYNAMICAL SYSTEM
Authors: CONTOPOULOS G. , LUKES-GERAKOPOULOS G. , APOSTOLATOS T. A.
Published: July 2011

We study the orbits in a Manko–Novikov type metric (MN) which is a perturbed Kerr metric. There are periodic, quasi-periodic, and chaotic orbits, which are found in configuration space and on a surface of section for various values of the energy E and the z-component of the angular momentum Lz. For relatively large Lz there are two permissible regions of nonplunging motion bounded by two closed curves of zero velocity (CZV), while in the Kerr metric there is only one closed CZV of nonplunging motion. The inner permissible region of the MN metric contains mainly chaotic orbits, but it contains also a large island of stability. When Lz decreases, the two permissible regions join and chaos increases. Below a certain value of Lz, most orbits escape inwards and plunge through the horizon. On the other hand, as the energy E decreases (for fixed Lz) the outer permissible region shrinks and disappears. In the inner permissible region, chaos increases and for sufficiently small E most orbits are plunging. We find the positions of the main periodic orbits as functions of Lz and E, and their bifurcations. Around the main periodic orbit of the outer region, there are islands of stability that do not appear in the Kerr metric (integrable case). In a realistic binary system, because of the gravitational radiation, the energy E and the angular momentum Lz of an inspiraling compact object decrease and therefore the orbit of the object is nongeodesic. In fact, in an extreme mass ratio inspiraling (EMRI) system the energy E and the angular momentum Lz decrease adiabatically and therefore the motion of the inspiraling object is characterized by the fundamental frequencies which are drifting slowly in time. In the Kerr metric, the ratio of the fundamental frequencies changes strictly monotonically in time. However, in the MN metric when an orbit is trapped inside an island the ratio of the fundamental frequencies remains constant for some time. Hence, if such a phenomenon is observed this will indicate that the system is nonintegrable and therefore the central object is not a Kerr black hole.
SUBCRITICAL PATTERN FORMATION IN GRANULAR FLOW
Authors: KANELLOPOULOS GIORGOS , VAN DER WEELE KO
Published: July 2011

We study a minimal model for the flow of granular material on a conveyor belt consisting of a staircase-like array of K vertically vibrated compartments. Applying a steady inflow rate Q to the top compartment, we determine the maximum value Q cr (K) for which a continuous flow through the system is possible. Beyond Q cr (K), which depends on the vibration strength and the dimensions of the system, a dense cluster forms in one of the first compartments and obstructs the flow. We find that the formation of this cluster is already announced belowQ cr (K) by the appearance of an oscillatory density profile along the entire length of the conveyor belt, with a distinct two-compartment wavelength.

These model predictions concerning the breakdown of the granular flow admit an elegant explanation in terms of bifurcation theory. In particular, the subcritical oscillatory pattern is shown to be a side effect of the period doubling bifurcation by which the uniform density profile (associated with a smooth particle flow) becomes unstable. The effect turns out to be robust enough to survive the presence of a reasonable amount of noise and even certain qualitative modifications to the flux model. The density oscillations may therefore well be of practical value and provide a warning signal for imminent clustering on actual conveyor belts.
MODIFIED PROJECTIVE LAG SYNCHRONIZATION OF TWO NONIDENTICAL HYPERCHAOTIC COMPLEX NONLINEAR SYSTEMS
Authors: MAHMOUD GAMAL M. , MAHMOUD EMAD E.
Published: July 2011

In this work, we introduce and investigate the modified projective lag synchronization (MPLS) of two nonidentical hyperchaotic complex nonlinear systems. The idea of an active control technique based on complex Lyapunov function with lag in time is used for an approach to investigate MPLS of hyperchaotic attractors of these systems. For illustration, this approach is applied to hyperchaotic complex Chen and Lü systems. Numerical results are calculated to test the validity of the analytical expressions of control functions to achieve MPLS.
JET RESULTS, JET RECONSTRUCTION, AND UNDERLYING EVENT STUDIES AT CDF
Authors:   FOR CDF COLLABORATION, ALON RAZ
Published: July 2011

We present recent results of jet studies from the CDF Collaboration. The inclusive jet cross section measurements using different clustering algorithms, dijet production, and vector boson plus jet production measurements, are discussed. We also present the first study of highly boosted and massive jets. The properties of these jets, including the mass of the jet and several other observables, such as angularity and planar flow, are discussed.
JET AND UNDERLYING EVENT MEASUREMENTS IN p+p COLLISIONS AT RHIC
Authors:   FOR THE STAR COLLABORATION, CAINES HELEN
Published: July 2011

The physics of hadron-hadron collisions is very complex involving both perturbative and non perturbative QCD. It is imperative to study p - p collisions in detail to provide a variety of measurements against which the theoretical calculations can be tested. Direct jet measurements, for instance, help address fundamental questions of the fragmentation process. They also form a critical baseline for comparisons of results from heavy-ion studies, where fragmentation functions are expected to be modified due to interactions with the hot and dense medium. Finally, it is important to understand how the beam-beam remnants, multi-parton interactions, and initial- and final-state radiation combine to produce the particles observed in the underlying event. I present results from p - p collisions at 200 GeV collisions as measured by the STAR experiment.
CHANGE AGENTS IN THE FIELD OF STRATEGIC ENVIRONMENTAL ASSESSMENT: WHAT DOES IT INVOLVE AND WHAT POTENTIALS DOES IT HAVE FOR RESEARCH AND PRACTICE?
Authors: KØRNØV LONE , LYHNE IVAR , LARSEN SANNE VAMMEN , HANSEN ANNE M.
Published: July 2011

One of the challenges facing strategic environmental assessment (SEA) is finding ways to work in research and practice allowing critical interrogation and appropriate action to support sustainability. The point of departure for this article is the hypotheses that a certain kind of cooperative knowledge-production, called Mode 3, where SEA researchers interact with the societal milieu as change agents, provides a potential for SEA research and practice to further sustainability. Based on literature and three cases, this paper seeks to contribute to two questions: 'what does acting as a change agent within the field of SEA involve?' and 'what potentials does it have for research and practice?' The three cases illustrate how Mode 3 can support reflective SEA practice and practice-based SEA research. Theoretically the current understanding and discussion on change agents is sharpened through the focus on real-life linkages, putting forward the contextual influence and the unpredictability related hereto.
SEMICENTRALISED WATER SUPPLY AND TREATMENT: OPTIONS FOR THE DYNAMIC URBAN AREA OF HANOI, VIETNAM
Authors: SCHRAMM SOPHIE
Published: July 2011

Hanoi, the capital of Vietnam, is experiencing rapid urbanisation coupled with high economic growth rates. This situation is both a challenge and an opportunity for the upgrading of existing technical infrastructures. Regarding wastewater treatment, the situation in Hanoi today is characterised by a lack of wastewater treatment plants, processing only a small fraction of the accumulating wastewater. Prevalent means of sanitation are septic tanks installed under buildings for the collection of domestic wastewaters, with overflowing liquids draining into the groundwater in an uncontrolled manner. This decentralised means of sanitation is therefore currently not able to clean domestic wastewaters in an effective way. This paper explores circumstances under which a semi-centralised approach can offer a sustainable solution to cope with these challenges in Hanoi. The approach has been designed to meet the challenges of fast growing urban areas around the world.
Geochemical evolution of sulphide-bearing waste rock soils at the Bingham Canyon Mine, Utah
Authors: Borden Rich
Published: July 2011

The soils forming on waste rock dump surfaces at the Bingham Canyon Mine have paste pH values ranging from 2.08 to 7.91. Paste conductivity, a measure of soil salinity, varies between 22 and 8750 μS cm
−1
. The primary controls on waste rock soil pH and salinity are the sulphide distribution in the waste rock, the amount of limestone present and the age of the waste rock dump surface. The average pH of recently exposed waste rock is 7.0 and the average conductivity is 1120 μS cm
−1
. Within six years of placement on the waste rock dumps the average pH declines to 4.7, further decreasing to 3.7 after 50 years. The average conductivity increases to 3000 μS cm
−1
within six years but then declines to 855 μS cm
−1
after 50 years. The sharp drop in pH, and the peak in salinity shortly after the waste rock is placed on the dumps, reflects the rapid release of acidity and sulphate caused by oxidation of newly exposed pyrite. The salinity of the soils begins to decline as pyrite becomes depleted and sulphate is flushed from the soil by infiltration and runoff more rapidly than it is replenished by sulphide oxidation.
Water-quality trends for a stream draining the Southern Anthracite Field, Pennsylvania
Authors: Cravotta C. A. , Bilger M. D.
Published: July 2011

Stream flow, chemical and biological data for the northern part of Swatara Creek, which drains a 112 km
2
area in the Southern Anthracite Field of eastern Pennsylvania, indicate progressive improvement in water quality since 1959, after which most mines in the watershed had been flooded. Drainage from the flooded mines contributes substantially to base flow in Swatara Creek. Beginning in 1995, a variety of treatment systems and surface reclamation were implemented at some of the abandoned mines. At Ravine, Pa., immediately downstream of the mined area, median SO
4
concentration declined from about 150 mg l
−1
in 1959 to 75 mg l
−1
in 1999 while pH increased from acidic to near-neutral values (medians:
c.
 pH 4 before 1975;
c.
 pH 6 after 1975). Fish populations rebounded from non-existent during 1959–1990 to 21 species identified in 1999. Nevertheless, recent monitoring indicates (1) episodic acidification and elevated concentrations and transport of Fe, Al, Mn, and trace metals during storm flow; (2) elevated concentrations of Fe, Mn, Co, Cu, Pb, Ni, and Zn in streambed sediments relative to unmined areas and to toxicity guidelines for aquatic invertebrates and fish; and (3) elevated concentrations of metals in fish tissue, notably Zn. The metals are ubiquitous in the fine fraction (<0.063 mm) of bed sediment in mining-affected tributaries and the main stem of Swatara Creek. As a result of scour and transport of streambed deposits, concentrations of suspended solids and total metals in the water column are correlated, and those for storm flow typically exceed base flow. Nevertheless, the metals concentrations are poorly correlated with stream flow because concentrations of suspended solids and total metals typically peak prior to peak stream stage. In contrast, SO
4
, specific conductance and pH are inversely correlated with stream flow as a result of dilution of poorly buffered stream water with weakly acidic storm runoff derived mainly from low-pH rainfall. Declines in pH to values approaching 5.0 during storm flow events or declines in redox potential during burial of sediment could result in the remobilization of metals associated with suspended solids and streambed deposits.
Treatment of acid mine drainage by four vertical flow wetlands in Pennsylvania
Authors: Demchak J. , Morrow T. , Skousen J.
Published: July 2011

Acid mine drainage (AMD) is a serious problem in many watersheds where coal is mined. Passive treatments, such as wetlands and anoxic limestone drains (ALDs), have been developed, but these technologies show varying treatment efficiencies. A new passive treatment technique is a vertical flow wetland or successive alkalinity producing system (SAPS). Four SAPS in Pennsylvania were studied to determine changes in water chemistry from inflow to outflow. The Howe Bridge SAPS removed about 130 mg l
−1
(40%) of the inflow acidity concentration and about 100 mg l
−1
(60%) iron (Fe). The Filson 1 SAPS removed 68 mg l
−1
(26%) acidity, 20 mg l
−1
(83%) Fe and 6 mg l
−1
(35%) aluminium (Al). The Sommerville SAPS removed 112 mg l
−1
(31%) acidity, exported Fe, and removed 13 mg l
−1
(30%) Al. The McKinley SAPS removed 54 mg l
−1
(91%) acidity and 5 mg l
−1
(90%) Fe. Acid removal rates at our four sites were 17 (HB), 52 (Filson1), 18 (Sommerville) and 11 (McKinley) g of acid per m
2
of surface wetland area per day (g/m
2
d
−1
). Calcium (Ca) concentrations in the SAPS effluents were increased between 8 and 57 mg l
−1
at these sites. Equilibrators, which were inserted into compost layers to evaluate redox conditions at our sites, showed that reducing conditions were generally found at 60 cm compost depths and oxidized conditions were found at 30 cm compost depths. Deeply oxidized zones substantiated observations that channel flow was occurring through some parts of the compost. The Howe Bridge site has not declined in treatment efficiency over a six year treatment life. The SAPS construction costs were equal to about seven years of NaOH chemical treatment costs and 30 years of lime treatment costs. So, if the SAPS treatment longevity is seven years or greater and comparable effluent water quality was achieved, the SAPS construction was cost effective compared to NaOH chemical treatment. Construction recommendations for SAPS include a minimum of 50 cm of compost thickness, periodic replacement or addition of fresh compost material, and increasing the number of drainage pipes underlying the limestone.
Ferrous oxidation chemistry in passive abiotic systems for the treatment of mine drainage
Authors: Dempsey Brian A. , Roscoe Heath C. , Ames Ryan , Hedin Robert , Jeon Byong-Hun
Published: July 2011

The rates of chemical oxidation and gas transfer were determined for two passive abiotic systems for the treatment of mine drainage. One system (HB) is a series of ponds whose discharge was net acidic. The second treatment system (CK) has shallow channels and net alkaline discharge. The O
2
mass transfer coefficient was 2 cm h
−1
for HB Pond #2 and ranged from 4 to 40 cm h
−1
for the CK channels, depending on channel velocity and depth. The CO
2
mass transfer coefficient was 1.3 cm h
−1
for HB Pond #2 and ranged from 1.4 to 15 cm h
−1
for the CK channels. Oxygen transfer appeared to be the rate-limiting step for oxidation of Fe(II) at HB Pond #2. The oxidation rate for Fe(II) adsorbed to already-formed ferric oxides (heterogeneous oxidation) appeared to control the rate of oxidation of Fe(II) at the CK channels. Based on field data, the heterogeneous rate constant for oxidation of Fe(II) was 6.0×10
−9
 mg l
−1
s
−1
at 17°C or k
2
of 5.5×10
−8
 mg l
−1
s
−1
at 25°C. This value was consistent with previously reported values for k
2
based on laboratory experiments. The annual-averaged iron removal rates were 18 g d
−1
m
−2
for HB and 42 g d
−1
m
−2
for CK, compared to empirical design expectations of 10 to 20 g d
−1
m
−2
. Heterogeneous oxidation accounted for >80 of the oxidation of Fe(II) at HB and >90% of the oxidation of Fe(II) at CK.
Hydrological and soil geochemical controls of the abundance and fractionation patterns of rare earth elements in a periodically acidic Boreal stream
Authors: Åström Mats
Published: July 2011

The concentrations and shale-normalized patterns of rare earth elements (REEs) were determined along the main stem of a medium-sized Boreal stream (catchment area, 107 km
2
), to which areas covered with acid sulphate soils, developed in sulphide-bearing marine sediments, drain. In the upper reaches (headwater), where there are no acid sulphate soils, the REE concentrations were low at all sampling events (e.g. Nd=1.0 to 1.3 μg l
−1
) and the shale-normalized profiles were characterized by peaked middle-REE enrichment (centred on gadolinium) with a secondary maximum at ytterbium (Yb)/lutetium (Lu). Downstream there was an increase in the REE concentrations caused by leaching of acid sulphate soils which increase in abundance towards the basin outlet. The strongest downstream increase occurred at high-water flow in autumn (Nd concentrations up to 53 μg l
−1
) and the weakest during baseflow conditions (Nd=2–7 μg l
−1
). Downstream, at elevated REE concentrations, there was a depletion of the heavy REEs caused by: preferential scavenging (and thus removal) of the heavy REEs by oxy-hydroxides contained in the source soil; preferential complexation of the light and middle REEs by the dissolved SO
4
2−
; and/or the existence of a source mineral (in the acid sulphate soils) depleted in the heavy REEs. In two tributaries and a first-order stream sampled on a single occasion, the REE features were consistent with those along the main stem. In a subsurface drainpipe, also sampled once, there was, however, a convex REE-fractionation pattern characterized by a stronger depletion from gadolinium (Gd) to lanthanum (La)- than from Gd to Lu. The origin of this pattern, which seems to be of minor importance in the REE-enriched waters in the catchment, remains unexplained.
A comparison of unsupervised neural networks and k-means clustering in the analysis of multi-element stream sediment data
Authors: Clare A. P. , Cohen D. R.
Published: July 2011

Isolation of complex patterns of correlation between variables, association among samples and anomaly identification, through conventional parametric multivariate statistical procedures, may be obscured by the presence of multivariate outliers and non-normal variable distributions. Procedures such as k-means clustering generally require substantial data pre-processing. Unsupervised neural networks (UNN) have the capacity to cluster multivariate data, using a modified form of the standard unsupervised Kohonen self-organizing map that is non-linear, non-parametric, rapid and robust. The number of clusters into which samples are allocated is determined by the unsupervised neural network and is directly dependent upon the original input data.

UNN and k-means clustering was performed on stream sediment geochemical data from 1670 sub-catchments in the northeast region of New South Wales. Both methods produced clusters for the feldspar-associated elements that were closely related to sub-catchment geology and topography. UNN clustering revealed more subtle variations within the major lithological groups. UNN clustering of Cu–Pb–Zn produced ten main clusters and identified 26 anomalies, that were mainly from sub-catchments, containing significant base metal mineralization occurrences. K-means clustering of transformed Cu–Pb–Zn yielded five major clusters and only 19 anomalies. Progressive increase in
k
from eight to 20 did not substantially alter the k-means classification of samples between common groups and anomalies. Some catchments identified only as anomalous by UNN clustering contain known base metal mineralization.
Weighted sums – knowledge based empirical indices for use in exploration geochemistry
Authors: Garrett Robert G. , Grunsky Eric C.
Published: July 2011

A background to the use of empirical indices (i.e. ratios and sums) in exploration geochemistry is presented, together with commentary on more sophisticated statistical multivariate procedures. Multivariate statistical procedures can assist in developing geochemical models upon which further investigations can be based, and in identifying geochemically anomalous samples. A case is made for a simple method, weighted sums, that is based on prior knowledge concerning the mineralogy and geochemistry of sought-after mineral resources. This procedure avoids many of the complications and pit-falls of more sophisticated multivariate statistical methods. Although weighted sums were introduced to exploration geochemistry over 20 years ago, they don’t appear to have been used extensively. The objective of this paper is to reintroduce them, with a simple but clear exposition, as a tool worthy of consideration in the knowledge-based 21st century.
A fractal filtering technique for processing regional geochemical maps for mineral exploration
Authors: Xu Yaguang , Cheng Qiuming
Published: July 2011

A regional geochemical map interpolated from point data, usually sampled in surficial media such as stream sediments or lake sediments, may contain a large amount of information critical for mineral exploration and environmental studies. The geochemical map is, however, not ‘ready-to-use’ for such tasks as the determination of a local ‘anomaly’ or the characterization of a regional trend of one or more chemical elements as may be required for the purpose of mineral resource prediction. This becomes possible only after the map has been clearly divided into different components. Fractal filtering, a recently developed technique for decomposing a map or image into different components, helps to separate the anomaly from background or to extract other meaningful patterns from the geochemical map using both frequency and spatial information.

The fractal filters are formed by applying the fractal concentration-area model to the power spectrum of the processed geochemical field. They often constitute a group of irregularly shaped filters in the frequency domain that can separate the domain of wave numbers into distinct regions, each with a power spectrum following a similar power-law or fractal property. The corresponding patterns of the separate components are obtained after transformation back to the spatial domain.

The fractal filter can be applied to decompose the original geochemical field into a set of map components with distinct scaling ranges and anisotropy. The analysis of relationships among these decomposed maps can provide useful information for the interpretation and evaluation of anomalies or trends.

This paper briefly introduces the theory behind the fractal filtering technique. A case study of regional geochemical data of lake sediments from western Meguma Terrain, Southern Nova Scotia, Canada, is used to illustrate application of this technique to process the regional geochemical maps of the study area for the prediction of the turbidite-hosted gold deposits.
Laterite geochemistry for regional exploration surveys – a review, and sampling strategies
Authors: Cornelius Matthias , Smith Raymond E. , Cox Amanda J.
Published: July 2011

Numerous orientation studies and regional sampling campaigns by CSIRO and, more recently, the Cooperative Research Centre for Landscape Evolution and Mineral Exploration (CRC LEME), over the past 20 years, have demonstrated that residual lateritic gravels and duricrust are useful sampling media for regional, district and detailed exploration for gold, base metals and rare metals in the Yilgarn Craton. This paper focuses on regional exploration.

A regional approach to geochemical sampling, using lateritic duricrust and lateritic gravels, based on regolith–landform models, is advocated. Sampling of areas of 10 000 km
2
or more, or integrating several data sets, is intended to identify geochemical trends and detect large geochemical haloes several hundred square kilometres in size, arising from concealed ore deposits or mineralized districts. In unexplored or underexplored regions, sampling at 3 km spacing on a triangular grid is appropriate at the reconnaissance stage. Results of this study show that, even if the sampling pattern is opened up to 9 km spacing, major trends can still be identified. In relict landform regimes, follow-up sampling should progressively close the spacing through 3 km, 1 km, 300 m, and less, in areas of interest. The effectiveness of a broad scale approach to laterite sampling is demonstrated by using As and Ni data for the southwestern part of Western Australia, where regional geochemical trends are apparent even at a 9 km sample spacing.

For regional sampling in semi-arid terrains, use of a helicopter is effective because it provides the geologist with the optimum view of the landscape for regolith–landform control, as well as flexibility to choose an appropriate site for sampling. Whereas lateritic residuum (ferruginous gravels and duricrust) represents the preferred sample medium for regional surveys, other ferruginous materials are also suitable, particularly at the follow-up stage. Assigning regolith codes to all sample media and categorizing each sample are essential. The codes become part of the geochemical database and allow valid statistical evaluation of data for specific regolith materials. In all cases, analysis of a multi-element suite, including target and pathfinder elements, is recommended. Multi-element analysis allows interpretation that can take into account variable characteristics due to sample matrix, landform position, weathering environment and gross bedrock lithology. Multi-element geochemistry also provides the opportunity for multi-commodity exploration.
Regolith evolution and geochemical dispersion in transported and residual regolith – Bronzewing gold deposit
Authors: Anand R. R. , Wildman J. E. , Varga Z. S. , Phang C.
Published: July 2011

Geochemical dispersion in the regolith was investigated at the Bronzewing gold deposit in a variety of geomorphological environments. A series of economic gold deposits are concealed by 5–35 m of sediments, and a thick residual profile about 100 m thick. Prior to mining, samples of regolith materials were collected from surface and drill cuttings, along several lines over the north–south trending, elongate zone of mineralization. These samples were examined in detail to determine element distributions, their relationship to regolith evolution and their significance to exploration.

The residual materials (lateritic residuum and ferruginous saprolite) have Au, W and Cu anomalies in the vicinity of the deposit. Elements associated with the Au mineralization in the lateritic residuum of the Laterite Pit are Ag, Ba, Ce, W, Mo, As, Sb and Cu. Gold anomalies in lateritic residuum are less consistent in the Discovery Pit and, at both the Central and Discovery Pits, are enriched in Cu and W only close to the weathered primary mineralization. Three-dimensional modelling indicates that Au in saprolite is localized and largely residual. Geochemical dispersion from primary mineralization into the sediments is only minor, except immediately overlying the lateritic residuum or saprolite. This dispersion is, however, almost entirely mechanical and there appears to have been little, if any, post-depositional chemical dispersion. Ferruginous mottles developed in palaeochannel sediments have very low Au contents (<5 ppb) but are slightly enriched in Cu. There is a significant concentration of Au (up to 300 ppb) in authigenic smectites formed at the residual-transported interface. The deposits are blind to soil sampling (10–30 cm depth) using total and several partial extraction techniques.

The results demonstrate that dispersion of ore-related elements at Bronzewing is mostly confined to the lateritic residuum and ferruginous saprolite and that sampling of these materials, even if buried beneath transported overburden, will readily locate deposits of this type. However, it is important to distinguish between residual and transported regolith, especially nodules and pisoliths. In the absence of residual materials, sampling of the lowermost sedimentary units (gravelly sediments), possibly including the unconformity, is recommended because it may show the geochemical dispersion that is wider than the primary anomaly in saprolite or bedrock. The results also provide strong support for the use of multi-element geochemistry, with elements such as Cu and W being enriched close to primary mineralization.
Geochemical exploration around the Harmony gold deposit, Peak Hill, Western Australia
Authors: Robertson I. D. M.
Published: July 2011

Primary Au mineralization at Harmony is associated with sulphide-poor quartz veins in mafic and ultramafic rocks. Gold and W are the most significant indicators of mineralization in fresh rock. Elements associated with the phyllic alteration halo are K, Rb and Ba, and Eu, Lu and Yb; these increase in abundance and range near mineralization. Although As and Sb are elevated, their abundances are far lower than in sulphide-rich mineralization styles. The Harmony gold deposit was completely covered by a blanket of soil and colluvium. Drilling beneath this revealed a complex, partly eroded residual regolith, clay-rich valley fill sediments and colluvium.

Sampling and analysis of the top of the basement (ferruginous saprolite, lateritic residuum and mottles washed from the mottled zone) on a 250 m sample spacing showed significant Au and W anomalies in the vicinity of the deposit. Gold dispersion in the ferruginous saprolite is restricted and requires close-spaced sampling (50 m).

The unconformity between the stripped basement and colluvium was sampled at a 150 m spacing to capitalize on any mechanical or hydromorphic dispersion along the contact. Dispersion of Au, W, Ta and Nb along this interface, indicating mechanical down-slope migration, produced better and more consistent anomalies than the basement sampling in this stripped environment. There are some very weak Au anomalies in the fine soil fraction (<75 μm), where the colluvial cover over the Harmony deposit was extremely thin (<2 m). However, this cannot be relied upon to locate mineralization.
Multi-element dispersion within salt-lake environments: case study of the buried Hannan South gold deposit, Western Australia
Authors: Lawrance Louisa M.
Published: July 2011

Prior to mining, the Hannan South deposit contained 0.26 Mt at 4.98 g t
−1
Au confined within a weathered, highly saline water-saturated regolith beneath a salt lake. There was no surface expression, although the host rock sub-cropped at 3–4 m depth. The water table seasonally fluctuates between 0 and 10 m depth. The rock is a highly altered and structurally disrupted basalt, now a sulphidic epidote-rich unit. This unit is truncated at 80 m depth within sub-vertically interlayered Archaean felsic sedimentary and intermediate volcanic rocks. No fresh host rock is preserved. There is a sharp sub-horizontal iron redox front at 25–30 m depth between upper and lower saprolite. At this front, Eh conditions are sufficient to oxidize dissolved Fe
2+
from weathered Fe-bearing minerals in the lower saprolite, to Fe
3+
with the production of strong acid solutions (pH 0.5–2). Acid-enhanced weathering forms the upper saprolite as the front descends through the profile. As the pH increases, Fe
3+
precipitates as Fe oxides, mainly goethite, above the front.

Primary Au containing 3–5 wt% Ag is hosted within pyrite and accessory sulphide minerals of As, Cu, Co, Pb, Bi, W and Zn in the saprock. The progressive oxidation of the sulphides has released soluble ore-associated elements, including Au as a thiosulphate complex (Au–Ag(S
2
O
3
)
2
3−
). This complex is metastable and has precipitated fine-grained secondary Au containing 3 wt% Ag around pseudomorphs of the host sulphides. The other elements are widely dispersed but are largely confined to the host rock in the lower saprolite due to limited groundwater flux. Poorly defined acid sulphide and subtle Mn redox fronts within the lower saprolite have little influence on trace element dispersion. Silver is the most strongly depleted. In the upper saprolite, descent of the redox front over time has led to leaching of Au under acid, oxidizing conditions. Gold has probably dissolved as organic or chloride complexes at the front, dispersed laterally down-gradient and precipitated as pure crystals (99.9 wt% Au) in a sub-horizontal supergene enrichment blanket just above the front. Copper, Ag, Co, Pb and Zn are also strongly leached from the acidic saprolite above the iron redox front and are dispersed and depleted with increasing groundwater flux in the upper profile. In comparison, As, Sb, Bi, Mo and W, which form oxyanions, are relatively immobile and are preferentially retained in goethitic zones. These buried multi-element halos hosted by goethite provide near-surface geochemical exploration targets within otherwise barren upper saprolite.