WHAT MINERALS AND HOW MUCH OF EACH WILL YOU LIKELY USE DURING
YOUR LIFETIME?
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How Mineral Deposits Are Formed Ore Deposits formed when metals
are concentrated in anomalously high amounts by geological
processes Mineral resources are usually extracted from ore
deposits
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ORIGINS OF MINERAL DEPOSITS Nine elements account for about 99%
of the earths crust by weight. The remainder are found in trace
amounts. O 45%; Si 27%; Al 8%, Fe 6%; Ca 5%; Mg 3%, Na 2%, K 2 %
titanium (Ti) 1%
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ORIGINS OF MINERAL DEPOSITS 1. PLATE BOUNDARIES Metal sulfides
are precipitated at divergent boundaries as hot water carries
dissolved metals to the surface. Convergent boundaries mobilize
metals in the molten rock, distilling and concentrating some such
as mercury (Hg).
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ORIGINS OF MINERAL DEPOSITS 2. IGNEOUS PROCESSES Ore deposits
form when magma cools Heavy sink Light float Hot water -->
dissolves --> also concentrates concentration
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ORIGINS OF MINERAL DEPOSITS 3. SEDIMENTARY PROCESSES sort by
size and weight
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ORIGINS OF MINERAL DEPOSITS 4. EVAPORITES when inland oceans
evaporate Marine evaporates (solids)-potassium and sodium salts,
gypsum, anhydrite Nonmarine evaporates (solids)-sodium and calcium
carbonate, sulfate, borate, mitrate, and limited iodine and
strontium compounds Brines (liquids derived from wells, thermal
springs, inland salt lakes, and seawaters)-bromine, iodine, calcium
chloride, and magnesium and sometimes heavy metals such as copper,
lead and zinc
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ORIGINS OF MINERAL DEPOSITS 5. BIOLOGICAL PROCESSES phosphates
and iron some could be formed only when lower oxygen in atmosphere
(Gray beds) Calcium minerals of shells and bones 31 different
Biologically produced minerals
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ORIGINS OF MINERAL DEPOSITS 6. WEATHERING PROCESSES
decomposition of rock --> bauxite or aluminum ore
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ORIGINS OF MINERAL DEPOSITS 7. OCEAN FLOOR DEPOSITS
Hydrothermal vents and divergent plate boundaries --> sulfide
deposits with zinc, copper, iron Sea water --> magnesium Ocean
floor --> manganese oxide nodules
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Secondary enrichment process
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Resources and Reserves Minerals are classified as: 1. Mineral
Resources Elements, chemical compounds, minerals or rocks that can
be extracted to obtain a usable commodity 1. Mineral Reserves The
portion of the resource that is identified and from which usable
materials can be legally and economically extracted at the time of
evaluation
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How Much Do We Use?? Metallic Vs. Non-Metallic Sodium and Iron:
100-1,000 million metric tons /year N, S, K, Ca: 10-100 million
metric tons /year Zn, Cu, Al, Pb: 3-10 million metric tons/year Ag,
Au: 10,000 metric tons/year
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Availability of Mineral Resources When the availability of a
mineral becomes limited, there are 4 possible solutions: 1. Find
more sources 2. Recycle and reuse what has already been obtained 3.
Reduce consumption 4. Find a substitute
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Impacts of Mineral Development Environmental Impacts Depends on
many factors mining procedures, climate, rock type, etc. Subsurface
Vs. Surface mining Social Impacts Increased demand for housing and
services in mining areas When ore is gone $ is gone and Jobs are
gone
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Minimizing Environmental Impact of Mineral Development
Environmental regulations at the federal, state and local levels
Reclaiming Stabilizing soils Controlling air emissions Preventing
contaminated water from leaving or treating contaminated water that
has left a mining site On-site and off-site treatment of waste
Practicing the 3 Rs of waste management
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Minerals and Sustainability R-to-C Ratio A measure of the time
available for finding the solutions to depletion of nonrenewable
resources R = known reserves C = rate of consumption Often
misinterpreted as the time a reserve will last at the present rate
of consumption. Is a present analysis of a dynamic system in which
both the amount of reserves and consumption may change over
time.