In search of a new China:mineral demand in South and Southeast Asia

China’s industrialisation transformed global markets for mineral commodities. As growth in China slows and becomes less material intensive, the question arises whether countries of South and Southeast Asia can take up the baton from China and give a further boost to global mineral demand. The economic prospects of South and Southeast Asia are undoubtedly promising, helped by growing populations and a fast-expanding middle class. However, the model of growth being embraced by these countries is different from that of China and likely to be less material intensive. Also, many of them are economically coming off a very low base. With respect to the supply of minerals to the region, the impact of India’s growth on global mineral markets will be limited by the fact that many of India’s mineral needs can be met from domestic sources. In Southeast Asia, some of the mineral requirements will be met from domestic resources while some of its requirements for finished metals will likely continue to be met from China which is a heavy investor in the region and which has massive surplus metallurgical capacity.</p

Stratified slopes, numerical and empirical stability analysis

Urbanisation means that many natural slopes in and around cities are often subjected to cuts resulting in dramatic changes in the geometry of slope faces mostly by increasing slope angle which could lead to failures with catastrophic consequences. As most natural slopes are of nonhomogeneous layered nature, understanding the stability behaviour of such slopes will be of utmost importance. The current practice in analysing slopes of complicated nature, geometrically and materially, is mostly to apply simplifications sacrificing accuracy leading to use of large factors of safety, which could undermine analytical and economic feasibility of projects. In this research limit-equilibrium and finite element methods are used, respectively by OASYS Slope and PLAXIS 2D, to empirically and numerically model and analyse geometrically non-homogeneous stratified slopes with the aim of understanding the effects of non-homogeneity of geometry and materials on stability under various inclination angles of slope face. The analysis included determination of factors of safety as well as a sensitivity analysis looking into the combined effects of contributing parameters

Assessing Marsh response from sea-level rise applying local site conditions: Humboldt Bay Wetlands

The broad goal of our research was to use site-specific data to develop local and regionally applicable models that inform management of tidal wetlands within Humboldt Bay. Our overarching question was: how vulnerable are Humboldt Bay tidal marshes to different rates of SLR. This question was addressed with three broad objectives: (1) Assess past patterns in sedimentation to inform current SLR projections. This was accomplished by radioisotope dating of stratigraphic cores. (2) Measure baseline conditions in the tidal marshes. We characterized physical and biological properties at all study sites including topography, accretion rates, emergent vegetation, water level, salinity, and water temperature. These results are summarized in the main document, (3) Model tidal marsh elevation and habitat change under three SLR scenarios. We evaluated the degree of marsh habitat change under low, mid, and high SLR scenarios with the WARMER model (Swanson et al., 2014) for all study sites

Assessing coastal manager science needs and disseminating science results for planning

To facilitate communication and outreach of sea-level tidal marsh modeling results, we convened managers, biologists, Tribes, and other important decision makers and partners and hosted in-person workshops with stakeholders in six Pacific coast estuaries. Our objectives were: (1) disseminate site-specific baseline data and modeling results, reveal coast-wide trends, and identify data gaps; (2) identify how local climate science results may be incorporated into habitat conservation, planning, and adaptation strategies; and (3) develop an understanding of coastal climate change science needs to inform the California and North Pacific Landscape Conservation Cooperatives

Bedrock erosion by root fracture and tree throw: A coupled biogeomorphic model to explore the humped soil production function and the persistence of hillslope soils

In 1877, G. K. Gilbert reasoned that bedrock erosion is maximized under an intermediate soil thickness and declines as soils become thinner or thicker. Subsequent analyses of this “humped” functional relationship proposed that thin soils are unstable and that perturbations in soil thickness would lead to runaway thinning or thickening of the soil. To explore this issue, we developed a numerical model that simulates the physical weathering of bedrock by root fracture and tree throw. The coupled biogeomorphic model combines data on conifer population dynamics, rootwad volumes, tree throw frequency, and soil creep from the Pacific Northwest (USA). Although not hardwired into the model, a humped relationship emerges between bedrock erosion and soil thickness. The magnitudes of the predicted bedrock erosion rates and their functional dependency on soil thickness are consistent with independent field measurements from a coniferous landscape in the region. Imposed perturbations of soil erosion during model runs demonstrate that where bedrock weathering is episodic and localized, hillslope soils do not exhibit runaway thinning or thickening. The pit-and-mound topography created by tree throw produces an uneven distribution of soil thicknesses across a hillslope; thus, although episodes of increased erosion can lead to temporary soil thinning and even the exposure of bedrock patches, local areas of thick soils remain. These soil patches provide habitat for trees and serve as nucleation points for renewed bedrock erosion and soil production. Model results also suggest that where tree throw is a dominant weathering process, the initial mantling of bedrock is not only a vertical process but also a lateral process: soil mounds created by tree throw flatten over time, spreading soil over bedrock surfaces

Understanding microwave induced sorting of porphyry copper ores

Global demand for minerals and metals is increasing. It has been established that the impact of mining and mineral processing operations must be reduced to sustainably meet the demands of a low grade future. Successful incorporation of ore sorting in flow sheets has the potential to improve energy efficiency by rejecting non-economic material before grinding. Microwave heating combined with infra-red temperature measurement has been shown to distinguish low and high grade ore fragments from each other. In this work, experimentally validated 2-D finite difference models of a theoretical two phase ore, representing typical fragment textures and grades, are constructed. Microwave heating is applied at economically viable energy inputs and the resultant surface thermal profiles analysed up to 2 minutes after microwave heating. It is shown that the size and location of grains can dramatically alter surface temperature rise at short thermal measurement delay times and that the range of temperatures increases with increasing fragment grade. For the first time, it is suggested that increasing the delay time between microwave heating and thermal measurement can reduce the variation seen for fragments of the same grade but different textures, improving overall differentiation between high and low grade fragments

Critical materials for infrastructure: local vs global properties

Introducing new technologies into infrastructure (wind turbines, electric vehicles, low-carbon materials and so on) often demands materials that are ‘critical’; their supply is likely to be disrupted owing to limited reserves, geopolitical instability, environmental issues and/or increasing demand. Non-critical materials may become critical if introduced into infrastructure, owing to its gigatonne scale. This potentially poses significant risk to the development of low-carbon infrastructure. Analysis of this risk has previously overlooked the relationship between the ‘local properties’ that determine the selection of a technology and the overall vulnerability of the system, a global property. Treating materials or components as elements having fixed properties overlooks optima within the local–global variable space that could be exploited to minimise vulnerability while maximising performance. In this study, a framework for such analysis is presented along with a preliminary measure of relative materials criticality by way of a case study (a wind turbine generator). Although introduction of critical materials (in this case, rare earth metals) enhances technical performance by up to an order of magnitude, the associated increase in criticality may be two or three orders of magnitude. Analysis at the materials and component levels produces different results; design decisions should be based on analysis at several levels

Engineer Intelligence Study No. 191, Terrain Analysis, Alaska Slope Region, Alaska, 1959

The summary on Page 5 is paraphrased as follows. This digital document is a generalized description of the Arctic Slope region -- an area covering approximately 70,000 square miles. Access to the region and the feasibility of various access routes are discussed. Location and extent of natural fuel supplies are given. Factors controlling outdoor work feasibility are summarized graphically on Page 19. A terrain analysis of each of the three major physiographic provinces of the region. Those provinces are the Arctic Coastal Plain, Arctic Foothills, and Brooks Range provinces. Geographic factors which affected cross-country movement, construction, and water supply within those provinces are evaluated. This document contains detailed Landforms and Physiographic Provinces..., Bedrock Geography..., and Surficial Deposits... maps. The distribution list names a number of Corps of Engineers intelligence organizations and the engineering officers of army formations which might be interested in operations in Alaska. The digital document contains a bibliography. High-resolution scans of the large maps (150 to 350 MB) are attached (below) as related files