This paper describes a soil extraction method developed to investigate the different chemistries of Au in various soils in the Yilgarn Craton. The extraction solution is 1 M sodium bicarbonater0.1 M potassium iodide, saturated with CO2 and adjusted to pH 7.4 with hydrochloric acid. A soil : solution ratio of 1 : 2 Žg : ml. is used. Two different methods were used: Ž1. net iodide-extractable Au, with solutions analysed directly for Au; Ž2. gross iodide-soluble Au, where activated carbon is added to the mixture and the carbon analysed at the end of the extraction, thus providing a measure of all Au dissolved during the extraction Žincluding that readsorbed during the net extraction.. Depending on the extraction conditions, there may be appreciable readsorption of Au, particularly for organic-rich ŽG50%. and Fe-rich lateritic soils Ž)80%.. This readsorption is enhanced by pulverizing to -75 mm. Consequently, for simple extractions longer than 1 day, pulverized soils give lower apparent Au solubility than do unpulverized soils. Unpulverized carbonate-rich soils show high Au solubilities and little Žoften -20%. readsorption, and consequently show high net iodide-solubilities. These readsorption phenomena could affect other methods used in exploration and should be thoroughly investigated before incorrect conclusions are drawn. The readsorption problems are removed by adding activated carbon to the extraction mixtures; the carbon adsorbs Au as it is dissolved from the sample and is subsequently analysed. However, different soil types still show distinctly different Au solubilities, which should be recognized for interpretation of extraction results. Again, this effect should be tested for other extraction techniques. A more intractable problem may be that biological cycling of the Au through plants and other organisms appears to cause high Au solubilities in many soils. This effect may obscure any potential ‘mineralization signature’ that is being tested by selective extractions, and could cause problems for any extraction method, no matter how well designed

In 1963 the Chairman of Metallurgical Engineering at Queen’s University of Kingston, Ontario, Canada encouraged me to apply for a position in his department. This led to an appointment as an Assistant Professor of Metallurgical Engineering with a mandate to teach undergraduate and graduate courses in Mineral Process Engineering. Graduating metallurgists take positions available to them in the mining industry and mill “metallurgists” were in strong demand. Discussions with industry-oriented colleagues at the Department of Energy, Mines and Resources (Mines Branch) and with senior operators and plant design personnel at conferences such as the Conference of Metallurgists provided details of jobs available Canada-wide. This helped to fortify course content.

There is nothing more essential to life on Earth than water. Yet, there is a global water crisis. People are struggling to access the quantity and quality of water they need for drinking, cooking, bathing, hand washing and growing their food. Rapid industrialization, population growth and unplanned urbanization have contributed to severe land and water pollution. The main sources of freshwater pollution can be attributed to direct discharge of untreated toxic industrial wastes and dumping of various industrial effluents. More than 40% of the world’s population resulted affected by water scarcity, and this problem is also featured in the UN Sustainable Development Goal 6 (SDG 6), “clean water and sanitation”. Currently, about 3 in 10 people lack safe drinking water and 6 in 10 lack inadequate sanitation systems. Globally, 844 million people lack access to clean water resulting in families and communities being locked in poverty for generations. Access to clean water as a stepping stone to development changes everything. Safe, secure, affordable and equitable access to clean water in particular for the poor is among the most relevant challenge to be faced in the next years. In 1993, the UN General Assembly designates March 22 as World Water Day and recognizes the importance of addressing the global water crisis each year with an amazing progress in making clean drinking water accessible to 2.6 billion people in developing countries from 1990 to 2015. There are still opportunities to multiply the benefits of clean water through improved sanitation and hygiene education <...>

Le Crétacé inférieur de LEstramadura, au Portugal, m'apparaissait, lors-que j'en entrepris Vêtude, comme un thème de recherches à la fois séduisant et redoutable. Séduisant, car tout examen systématique avait été abandonné depuis plus de soixante ans, en dépit de la présence de classiques ensembles stratigraphiques, de la richesse des faunes et de la variété des fácies. Redoutable, car il m'amenait à suivre les traces de cet illustre géologue que fut Choffat. II était bien évident que je ne pouvais mener cette tache à son terme que grâce à de nombreux et bienveillants appuis. I'en ai large-ment beneficie, sinon même abuse. II m'est donc particulièrement agréable de remercier aujourd'hui tous ceux qui, durant les longues années de travail, m'ont aidé, conseillé et encouragé