Gold Mining PDF

What is the nature of white and black smokers? What is their difference in temperature and elements? What is the “smoke”? Where do these occur and what is the life there? White smokers: Lower temperature (30–350°C), emit lighter-colored minerals, mostly calcium and barium and silicon. LOWER TEMP, EM...

What is the nature of white and black smokers? What is their difference in temperature and elements? What is the “smoke”? Where do these occur and what is the life there? White smokers: Lower temperature (30–350°C), emit lighter-colored minerals, mostly calcium and barium and silicon. LOWER TEMP, EMIT LIGHTER COLORED MINERALS LIKE BARIUM AND CALCIUM Black smokers: Higher temperature (up to 400°C), emit dark mineral particles, mostly iron and sulfur. HIGHER TEMP, EMIT DARKER MINERALS LIKE IRON AND SULFUR "Smoke" is mineral-laden water. SMOKE WATER WITH LOTS OF MINERALS Location: Oceanic ridges and volcanic areas such as hotspots. Average depth ~2,000m Life: Hosts extremophiles (bacteria, tube worms, clams). EXTREMOPHILES Both H2O and CO2 are common volatiles. Why are they considered as “fluids” at modest temperatures and pressures? What other volatile elements are present in hydrothermal systems? Considered "fluids" at modest temperatures and pressures due to their ability to dissolve and transport materials. The critical point happens because the DV from the gas to the liquid phase decreases to 0, meaning they are no longer different phases AT LOW P BOTH HAVE LIQUID AND GAS PHASE, CRITICAL POINT WHERE BOTH LIQUID Other volatiles: Hydrogen sulfide, methane, nitrogen. What is the nature of solid solution between gold, silver, and copper? What is their atomic structure and atomic bonding. What physical properties are a result? Which is the heaviest and the lightest in terms of specific gravity. How does an alloy of these elements change color with composition? Atomic structure: Face-centered cubic lattice. Gold has continuous solid solution with Ag and Cu. Isostructural (CCP or FCC) Bonding: Metallic bonding. Physical properties: High conductivity, malleability. Specific gravity: Gold is heaviest, silver intermediate, copper lightest. Alloy color change: Varies with composition; more gold gives a yellow hue, more copper a red tint, silver adds whiteness. GOLD CONTINUOUS SOLID SOLUTION WITH SILVER AND COPPER. CCP OR FCC. METALLIC BONDING, HIGHLY MALLEABLE AND GOOD CONDUCTIVITY. GOLD HEAVIEST, THEN SILVER, THEN COPPER, YELLOW WITH GOLD, REDDISH WITH COPPER, WHITISH SILVER What is cinnabar and how was it useful in the gold rush? What is the process in making it useful? What are the environmental concerns? Cinnabar: Mercury sulfide (HgS). Source of mercury for gold extraction. Heated to extract mercury. Mercury pollution and toxicity. MERCURY SULFIDE FOR PROCESS OF AMALGAMATION AND HEATING TO CREATE GOLD AND MERCURY COMPOUND, POLLUTION AND TOXICITY CONCERN Why are quartz veins important in the finding of gold and other ores? Quartz veins often host gold and other ore minerals due to hydrothermal processes. Many hydrothermal deposits are associated with large igneous systems and derived quartz veins HYDROTHERMAL PROCESSES HOST OF GOLD AND ORES, LARGE IGNEOUS SYSTEMS What is gossan and why is it important to the finding of sulfide-bearing ore bodies? INDICATES PRESENCE What minerals occur in the gossan zone, the leached zone, the enriched zone, and the primary ore? IRON, CLAY, GOLD SILVER COPPER, SULFIDE Weathered zone of oxidized ore bodies. Indicates presence of sulfide ores. Minerals by zone: Gossan zone: Iron oxides. Leached zone: Clays, oxides, carbonates. Enriched zone: Copper, silver, gold. Primary ore: Sulfide minerals. What is realgar and why is it referred to as “powder of the mine”? Arsenic sulfide, bright red mineral. Nicknamed for its powdery form and use in early mining. BRIGHT RED, ARSENIC SULFIDE, POWDERY FORM USED IN MINING What is the “resource curse”? Countries with rich resources often face economic and political challenges due to dependency. COUNTRIES WITH LOTS OF RESOURCES ECONOMIC AND POLITICAL CHALLENGES DUE TO DEPENDENCY What is acid mine drainage? How does this happen? Occurs when sulfide minerals are exposed, forming sulfuric acid. Acidifies waterways, harms ecosystems. What are the environmental effects of mining? Deforestation, habitat loss, water contamination, air pollution, soil erosion. From “Deepest Gold Mine in Planet Earth” How deep is this mine and where is it? New drilling will go to what depth? Approximately 4 km deep, located in South Africa. New drilling goal: 4.5 km. When was this gold ore deposit first discovered? Discovery: Early 20th century. How hot is the temperature? What is the origin of the heat? Temperature: Reaches up to 60°C, heat from Earth's core. Other than explosions, what is the greatest danger in the mine? Rock bursts from pressure. What is the origin of the gold and how old is it? What is the rock type that holds the ore? Ancient placer deposits in conglomerate rock. How is the gold extracted from the ore? Crushing, grinding, cyanidation. When the miners blast the explosive, why must they keep the mouths open? Prevents eardrum damage from pressure change.