Table of Contents

Abstract: Oxidation of iron sulfides in waste rock dumps and tailings deposits may result in formation of acid rock drainage (ARD), which often is a challenging problem at mine sites. Therefore, integrating an ARD management plan into the actual mine operations in the early phases of exploration, continuing through the mine life until final closure might be successful and decrease the environmental impact. A thorough characterization of ore and waste should be performed at an early stage. A detailed knowledge of mineralogical composition, chemical composition and physical properties such as grain size, porosity and hydraulic conductivity of the different waste types is necessary for reliable predictions of ARD formation and efficiency of mitigation measures. Different approaches to prevent and mitigate ARD are discussed. Another key element of successfully planning to prevent ARD and to close a mining operation sustainably is to engage the mine stakeholders (regulators, community and government leaders, non-governmental organization (NGOs) and lenders) in helping develop and implement the ARD management plan.

Abstract: In several recent models of invertebrate skeletogenesis, Ca-carbonate crystallization occurs within a liquid-filled chamber. No explanation is given neither for the simultaneous occurrence of distinct polymorphs of Ca-carbonate within these liquid volumes, nor for the spatial arrangement of the mineral units which are always organized in species-specific structural sequences. Results of a series of physical characterizations applied to reference skeletal materials reveal the inadequacy of this liquid-filled chamber model to account for structural and chemical properties of the shell building units. Simultaneously, these data provide convergent pieces of evidence for a specific mode of crystallization developed throughout various invertebrate phyla, supporting the hypothesized “common strategy” based on a multi-scaled control exerted on formation of their calcareous hard parts.

Abstract: Mollusk shells, especially the nacre, are of commercial interest as well as palaeoenvironmental proxies. They are also investigated as biomaterials for medical purposes and biomimetics. Although the mineralogy is well-known and unique (aragonite tablets), the organic components are various. However, determination of the precise composition of the soluble organic matrix (SOM) of the nacreous layer is difficult. Among the range of possible techniques, 1D electrophoresis and High-performance liquid chromatography (HPLC) have previously been applied separately to differentiate pI and molecular weights. To date, no clear correlation has been established between the two parameters obtained in such conditions. Here, we report the use of preparative electrophoresis, coupled with HPLC, to determine the molecular weights of the pI fractions. The results are compared with 2D gel electrophoresis. It is shown that both methods have drawbacks and advantages, and are not redundant. The complexity of the composition of the nacreous tablet shown by scanning electron microscope (SEM) and Atomic Force Microscope (AFM) observations is also evidenced by electrophoresis and HPLC.

Abstract: Nacre, or mother of pearl, is composed of aragonite tablets and is produced by some mollusks. Because of the highly organized internal structure, chemical complexity, mechanical properties and optical effects of nacre, its formation is among the best-studied examples of calcium carbonate biomineralization. The pearl oyster Pinctada margaritifera is harvested in French Polynesia for pearl farming. The quality of the pearl depends on the quality of the nacre on its surface and its iridescent colors are affected by the thickness of the layers. Here we report on an experimental study conducted to influence the shape and the thickness of nacre tablets by keeping pearl oysters at four different depths (7, 20, 30 and 39 m) for one week. Scanning electron microscopy was used to measure the thickness of the nacre tablets and to analyze their final shape. The shape of the tablets changed from hexagonal to rhomboid at a depth of 39 m. The change in shape led to a change in size. The thickness of the tablets was reduced by between 16 and 30% on average. We also measured the oxygen isotopic composition using Secondary Ion Mass Spectrometry. In this study, we demonstrated that depth can modify the size, shape and thickness of nacre tablets, but not the d¹⁸O. This environmental modification is important for the biomineralization of the shell of the pearl oyster Pinctada margaritifera.

Abstract: This paper critically assesses if accessible lithium resources are sufficient for expanded demand due to lithium battery electric vehicles. The ultimately recoverable resources (URR) of lithium globally were estimated at between 19.3 (Case 1) and 55.0 (Case 3) Mt Li; Best Estimate (BE) was 23.6 Mt Li. The Mohr 2010 model was modified to project lithium supply. The Case 1 URR scenario indicates sufficient lithium for a 77% maximum penetration of lithium battery electric vehicles in 2080 whereas supply is adequate to beyond 2200 in the Case 3 URR scenario. Global lithium demand approached a maximum of 857 kt Li/y, with a 100% penetration of lithium vehicles, 3.5 people per car and 10 billion population.