Mineral Resources and Environment

1. Mineral Resources and Environment Mineral Resources – elements, compounds, minerals, or rocks concentrated in a form that can be extracted to obtain a usable commodity Reserves – that portion of a resource that is identified and currently available (i.e. from which usable materials can be legally and economically extracted at the time of evaluation).

2. Minerals and Human Use Categories: 1. Metal Production & Technology 2. Building Materials 3. Minerals for Chemical Industry 4. Minerals for Agriculture

3. Mineral Products in a Typical Home

4. Mineral Depletion Curves Basic problem w/ availability of resources is not exhaustion, but cost of maintaining adequate reserves. At some pt., cost of mining exceeds value of the resource. Options: find more, find a substitute, recycle/reuse what we have, use less and increase efficiency of use, do without Choice depends on: Economics, Social factors, Environmental factors • Hypothetical Depletion Curves: • 1. Rapid consumption‑‑the most common pattern except for precious metals (PGM) • 2. Consumption with conservation • 3. Consumption, conservation, and recycling

5. Crushed Stone Sand and gravel Salt Gypsum Phosphate Potash Iron Aluminum Zinc Lead Copper 4.6 tons 3.2 tons 396 pds 206 pds 374 pds 48 pds 570 pds 48 pds 11 pds 11 pds 20 pds U.S. per Capita Consumption • Rates of Use • Fe and Na‑‑very high, about 1 billion tpy • N,S,K, and Ca‑mod high as fertilizers‑‑10 to 100 mtpy • Zn, Cu, Al, and Pb‑‑3 to 10 mtpy • Au and Ag about 10,000 tpy

6. Reliance on Imports

7. Geology of Mineral Resources • Aspects and processes of the geologic cycle are responsible for producing local concentrations of minerals • Genesis of Common Mineral Resources • Plate tectonics and minerals • Mobilization of elements at convergent boundaries due to partial melting (Hg in volcanic rocks) • Concentration • Ore = rock body containing valuable elements/metals that can be extracted • Concentration factor = ratio of necessary concentration (in ore) for profitable mining to average concentration in Earth’s crust

8. Plate Tectonics and Minerals • Plate boundaries are related to origin of iron, gold, copper, and mercury ore deposits • Metallic ore deposits & divergent plate boundaries: circulation of water through fractured, basaltic rock concentrates metallic sulfides as precipitates • Convergent plate boundaries concentrate metallic ores through partial melting of oceanic lithosphere at a subduction zone – high P & T releases metals from melts, concentrating them.

9. Mercury Deposits Example

10. Geology of Mineral Resources • Igneous processes • Kimberlite – diamond xtals in coarse grained igneous rock, originally formed at high P (deep) and have been moved to surface • Crystal settling • Late magmatic • Hydrothermal (hot water) ore deposits • Metamorphic processes • Contact metamorphism • Regional metamorphism

11. Geology of Mineral Resources • Sedimentary processes • Processes • Transport • Separation by size, shape, and density • Materials • Sand and gravel‑old rivers, beaches, and glacial deposit • Placer deposits‑gold and diamonds; separated by density from running water and on beaches • Evaporites‑‑seas that are separated or in internal drainage basins • Marine (K and Na, gyp, anhydrite) • Non‑marine (CO3, sulfates, borate, nitrate, I, and Br) • Brines (Br, I, CaCl2, Mg) • Salt domes‑‑for salt, sulfur, and oil; potential sites for radioactive waste