Ass #4 -Diamond Exploration & Mining Overview
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Questions and Answers

Which method involves analyzing the chemical composition of samples when indicator minerals are not located?

  • Character Sampling
  • Microdiamond testing
  • Seismic surveys
  • Geochemical testing (correct)
  • What is the purpose of the microdiamond testing stage in diamond recovery?

  • To determine the overall size of the deposit
  • To evaluate the clarity and color of diamonds
  • To perform geochemical analysis of soils
  • To find tiny diamonds in extracted samples (correct)
  • Which sampling method provides information about diamond size, shape, clarity, and color based on processing a large quantity of earth?

  • Bulk Sampling
  • Core Sampling
  • Geochemical Sampling
  • Character Sampling (correct)
  • What is assessed during the character sampling phase in the diamond recovery process?

    <p>Physical characteristics of diamonds</p> Signup and view all the answers

    What is indicated when indicator minerals such as garnet or chromite are found during exploration?

    <p>They signify the proximity to a diamond pipe</p> Signup and view all the answers

    Which method is commonly used for modern exploration of alluvial deposits?

    <p>Aerial photography</p> Signup and view all the answers

    What is the primary characteristic of secondary diamond deposits?

    <p>They formed from eroded primary deposits, resulting in higher diamond concentrations.</p> Signup and view all the answers

    Which of these statements best describes the location of most diamond-bearing kimberlites?

    <p>They predominantly exist on ancient cratons.</p> Signup and view all the answers

    What is the significance of cratons in diamond exploration?

    <p>They provide a denser substrate for sound waves indicating potential deposits.</p> Signup and view all the answers

    What technique involves analyzing soil for evidence of diamonds in exploration?

    <p>Soil sampling</p> Signup and view all the answers

    What typically happens to heavily included diamonds during the secondary deposition process?

    <p>They are broken down, leaving only higher-quality crystals.</p> Signup and view all the answers

    What is a significant factor that influences the strength of river currents in the secondary deposition of diamonds?

    <p>The volume of water flow during different seasons.</p> Signup and view all the answers

    What is the estimated time frame to go from diamond exploration to the first mining of diamonds?

    <p>Over 10 years</p> Signup and view all the answers

    What is the primary purpose of the sizing step in diamond recovery?

    <p>To reduce ore size for easier management</p> Signup and view all the answers

    Which recovery method utilizes the property of diamonds to stick to grease?

    <p>Grease belt separation</p> Signup and view all the answers

    In diamond mining, what is the significance of X-ray separation?

    <p>It uses the fluorescence of diamonds under X-rays</p> Signup and view all the answers

    What distinguishes onshore marine mining from other mining methods?

    <p>It requires special tools for dislodging diamonds</p> Signup and view all the answers

    Why has there been a shift from alluvial to primary deposits in diamond mining?

    <p>Technological advancements made locating primary deposits more effective</p> Signup and view all the answers

    What is the primary mining method used in cave mining for diamonds?

    <p>Drilling and blasting</p> Signup and view all the answers

    What is a notable characteristic of alluvial mining in terms of diamond production?

    <p>It is not economical for larger mining companies</p> Signup and view all the answers

    How does marine mining differ from traditional land mining methods?

    <p>It involves multiple methods including shallow and deep-sea operations</p> Signup and view all the answers

    What is the initial action taken when starting an open-pit mining operation?

    <p>Removal of overburden covering the pipe</p> Signup and view all the answers

    What is the primary purpose of horizontal tunnels in an underground mine?

    <p>To extract ore directly from the diamond pipe</p> Signup and view all the answers

    What type of charge is typically used to blast ore in open-pit mining to minimize damage to diamonds?

    <p>Low-velocity charges</p> Signup and view all the answers

    How do the characteristics of an open-pit mine change as it deepens?

    <p>The quantity of diamonds decreases and it becomes narrower</p> Signup and view all the answers

    What method is employed to create access for mining in an underground operation?

    <p>Constructing a series of vertical shafts</p> Signup and view all the answers

    What is one method used in diamond exploration that involves the use of sound waves?

    <p>Seismic surveys</p> Signup and view all the answers

    What is the main purpose of character sampling in diamond exploration?

    <p>To provide an overview of diamond size, shape, clarity, and color</p> Signup and view all the answers

    Which method is commonly used to look for tiny diamonds in a rock sample?

    <p>Microdiamond testing</p> Signup and view all the answers

    What type of surveys are widely used in diamond exploration to detect variations in magnetic response?

    <p>Magnetic surveys</p> Signup and view all the answers

    Which indicator mineral is NOT commonly associated with kimberlite or lamproite?

    <p>Quartz</p> Signup and view all the answers

    What is the primary process used in cave mining for removing ore?

    <p>Allowing the ore to fall as it is drilled</p> Signup and view all the answers

    What is the role of the cyclone in the Dense Media Separation process?

    <p>To create a centrifugal force that separates materials</p> Signup and view all the answers

    How does the grease belt method assist in diamond recovery?

    <p>By allowing diamonds to adhere to grease while washing away other materials</p> Signup and view all the answers

    Which factor primarily differentiates alluvial mining from primary deposit mining?

    <p>Alluvial deposits are typically more concentrated with diamonds</p> Signup and view all the answers

    What is a significant challenge of large-scale alluvial mining for larger companies?

    <p>The low yield of diamonds per area mined</p> Signup and view all the answers

    What technique is most commonly used for marine mining operations?

    <p>Deep-sea mining with high-tech vessels</p> Signup and view all the answers

    What is the main advantage of using modified alluvial mining methods?

    <p>Ability to process large volumes of material quickly</p> Signup and view all the answers

    What is the primary mining technique used to extract diamonds from underground deposits?

    <p>Cave mining</p> Signup and view all the answers

    What type of rocks are primarily associated with diamond formation?

    <p>Peridotite and eclogite</p> Signup and view all the answers

    What is the most common source of blue color in diamonds?

    <p>Boron</p> Signup and view all the answers

    Which of the following igneous rocks is much more commonly associated with diamonds?

    <p>Kimberlite</p> Signup and view all the answers

    What is the primary condition needed for diamonds to form in mantle keels?

    <p>Extreme pressures and temperatures</p> Signup and view all the answers

    How were diamonds primarily delivered to the Earth's surface?

    <p>By transportation in kimberlite and lamproite</p> Signup and view all the answers

    What characterizes carbonado diamonds?

    <p>They consist of many interlocking tiny diamond crystals.</p> Signup and view all the answers

    Which layer of the Earth is referred to as the 'crust'?

    <p>The surface and outermost layer of the Earth.</p> Signup and view all the answers

    What is the primary geological process that brings diamonds to the surface?

    <p>Eruption.</p> Signup and view all the answers

    What term describes the large, ancient, stable parts of Earth's landmasses?

    <p>Cratons.</p> Signup and view all the answers

    Which of the following statements distinguishes metamorphic rock?

    <p>It is formed through alteration by heat and pressure.</p> Signup and view all the answers

    What is a key factor in the formation of most diamond deposits?

    <p>Proximity to cratons.</p> Signup and view all the answers

    What best defines the geothermal gradient?

    <p>Rate of temperature increase with depth in the Earth.</p> Signup and view all the answers

    What is the primary component of carbonate compounds?

    <p>Carbon and oxygen.</p> Signup and view all the answers

    Study Notes

    Diamond Exploration & Mining

    • Primary Deposits: Diamonds found in kimberlite or lamproite pipes that brought them to the surface.
    • Secondary Deposits: Diamonds found outside pipes, often in alluvial (river) or marine deposits. Secondary deposits are typically richer in higher-quality diamonds due to erosion.
    • Diamond Exploration Process: Takes over 10 years, beginning with searching for deposits and culminating in mining. Clifford's rule notes that kimberlites occur on cratons. Scientists now look at areas around cratons, too. Sound waves were initially used to locate diamond deposits based on how density affects wave speed. This was superseded by other methods like gravity surveys (variations in ground density to locate pipes), magnetic & electromagnetic surveys (sending/detecting energy waves to map underground rock formations) and seismic surveys (similar to magnetic and electromagnetic surveys, but using sound waves).
    • Locating Deposits: Indicator minerals like garnet, spinel, diopside, olivine, ilmenite, chromite, & perovskite can signal nearby kimberlite or lamproite pipes. Geochemical testing of rock, soil or vegetation is also used, for example examining chemical composition.
    • Testing Deposit Viability: Samples are taken to test for the presence and type of diamonds, size, shape, clarity and color. Microdiamond testing analyzes cores from primary deposits or from sediments for secondary deposits. Character sampling assesses 500 tons of earth to determine ore grade (diamond concentration per 100 tons of rock). Bulk sampling of 5,000-10,000 tons is used for accurate evaluation.
    • Primary Deposit Mining: Digging out materials around the pipe to get the diamonds.
    • Open Pit Mining: Removing overburden (rock/soil) above the pipe, blasting the ore, and then excavating the remaining material.
    • Underground Mining: Tunneling into and around the pipe to access the ore. Drifts are drilled to extract ore.
    • Diamond Recovery: Ore is reduced in size for easier processing. Dense media separation is used to separate diamond-bearing ore from lighter waste materials. Grease belt and X-ray separation are other recovery methods that rely on different properties of diamonds vs the other minerals mixed in with the ore.

    Major Diamond Sources

    • Africa: Major producers, including Botswana with the Orapa and Jwaneng mines and Russia.
    • Australia: Had major diamond production (Argyle), but production drastically decreased starting in 2020.
    • Americas: Canada is an important producer with the Ekati and Diavik mines. The US has low economic significance in diamond mining.
    • Eurasia: India was once a main producer, but Russia has taken a lead role.

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    Description

    This quiz covers the key aspects of diamond exploration and mining, including primary and secondary deposits. It details the exploration process, methods for locating diamond deposits, and insights into the geological formations involved. Test your knowledge on diamond mining techniques and terminology.

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