ABSTRACT Two construction aggregate companies, Cemex and Hanson Aggregates, operate respective crushed stone quarries on the east and west slopes of Mount Zion in Clayton, California. These sidehill quarries utilize a single highwall and mine Jurassic diabase of the Coast Range ophiolite that formed as a sheeted dike complex. Hydrothermal veins, some containing 20%–30% disseminated pyrite and chalcopyrite, cut the diabase. The east quarry, operated by Cemex, was started by the Harrison-Birdwell Company in 1947. The west quarry, operated by Hanson, was started by the Henry J. Kaiser Sand and Gravel Company in 1954. The Cemex quarry highwall is visible as you come into the city of Clayton on Marsh Creek Road, with a height of ~280 m (920 ft). The height of the highwall at the Hanson quarry is ~215 m (700 ft). Both operations remove weathered diabase overburden to expose fresh diabase, which is drilled, blasted, and hauled to the plant for processing. To ensure aggregate is suitable for construction, quality assurance testing is conducted in accordance with the specifications of various agencies. These quarries supply the surrounding area with aggregate for hospitals, schools, highways, dams, and other buildings. Noteworthy projects supplied by the Clayton quarries include the Concord BART Station, Interstate-680, Interstate-580, Calaveras Dam, Sherman Island Levee, Highway 4, Highway 24, and Bay Bridge epoxy asphalt. Before aggregate was mined, Mount Zion was the site of a copper rush from 1862 to 1864. Gold and silver were also reported in various assays from the Clayton district. Although prospecting created excitement around Clayton, no productive orebodies were ever discovered.

Abstract Social development and rapid growth in the world's population has followed a remarkable technological development the past hundred years. Revolutions in agriculture and industry, medical innovations and new production technologies, have led to an increased standard of living for a larger part of the Earth's population. Megatrends for future developments are lining up and predictions for the next 40 years are numerous. Most ideas about our future societies imply new and innovative geo-scientific achievements. Towards 2058, we will have virtually surveyed and mapped every corner of the Earth. We will have detailed 3D images of the urbanized areas, and 4D models to assist to make reliable forecasts in a world of increased pressure on the natural resources and changing ecosystems. By 2058 the Green Stone Age is established, and we will use all elements in the periodic system and more rare minerals to support new materials and technological solutions. The major energy supplies will be CO 2 free. The agriculture will be more efficient, distribution and consumption of food will be more rational, and we will harvest from more marine food chains than today. More than 70% of the people on Earth will live in megacities and urban areas. Our cities will become smarter and greener, cars and public transport will be self-driving and autonomous tools using artificial intelligence to automate functions previously performed by humans. Substantial resources will be used to repair damaged ecosystems, and most important, we will use materials and products that have fewer negative consequences for the environment. The 17 UN goals for sustainable development are guidelines into the future, and geological surveys should serve as key instruments in the transformation into smarter and more sustainable societies. We are already on our way providing critical minerals for low carbon energy solutions, marine knowledge for blue growth, plans for green and smarter cities, and advanced digitalization for public services, as shown by examples in this present paper.

Abstract The largest UNESCO World Heritage Site in the UK is found in Cornwall and west Devon, and its designation is based specifically on its heritage for metalliferous mining, especially tin, copper and arsenic. With a history of over 2000 years of mining, SW England is exceptional in the nature and extent of its mining landscape. The mining for metallic ores, and more recently for kaolin, is a function of the distinctive geology of the region. The mining hazards that are encountered in areas of metallic mines are a function of: the Paleozoic rocks; the predominant steeply dipping nature of mineral veins and consequent shaft mining; the great depth and complexity of some of the mines; the waste derived from processing metallic ores; the long history of exploitation; and the contamination associated with various by-products of primary ore-processing, refining and smelting, notably arsenic. The hazards associated with kaolin mining are mainly related to the volume of the inert waste products and the need to maintain stable spoil tips, and the depth of the various tailings’ ponds and pits. The extent of mining in Cornwall and Devon has resulted in the counties being leaders in mining heritage preservation and the treatment and remediation of mining-related hazards.