Mining and Mineral Resources

Natural resources extraction Natural resources - materials or substances such as minerals, forests, water, and fertile land that occur in nature and can be used for economic gain.

Nonrenewable Mineral Resources Earth crust = Minerals + rock Minerals –inorganic compound that occurs naturally in the earth’s crust Solid Regular internal crystalline structure. Rock – solid combination of 1 or more minerals.

Mineral Resource: Any mineral useful to humans Metallic Minerals: Iron Oxide, Gold Non-metallic mineral: Limestone, sand Fossil Fuel; Coal, Petroleum Ore: A rock that can be profitably mined for a mineral or for minerals ( often metals) High Grade Ore; has high concentration of the mineral Low Grade Ore: smaller concentration

Types of Metals Abundant Metals: concentration >0.1% in the earth’s crust Iron, Aluminum, Silicon, Magnesium, Titanium, Manganese Scarce Metals: <0.01% in the crust Ferro-alloys: Nickel, Chromium Base Metals: Copper, Lead, Zinc Precious or Noble Metals: Gold, Silver, Platinum

Mineral Resources – Provide the materials used to make most of the things of industrial based society What are some of the effects caused by this demand? Where are they located?

Highly Uneven Distribution S Africa 50% Gold 75% Chromium 90% Platinum Group USA 50% Molybdenum 15% Lead Chile 30% Copper Cuba 40% Nickel Guinea and Australia 25% each of Aluminum Zaire 50% cobalt

Mineral Supply and Demand World Scenario: Iron, Aluminum, Chromium, Cobalt and Platinum will last centuries Copper, Lead, Zinc, Gold and Silver will last several decades only Ditto for phosphates and sulfur

Reducing consumption issues Less extended family households more leisure and travel, convenience, status etc. New technology adds to the existing needs e.g., cellular phones, computers, microwave oven In the US, population grew by 65% and consumption grew by 130% between 1950- 1990 Great demand for resources in the developing countries where there is a genuine need and where the great majority lives

If demand cannot be reduced, supplies must be increased, extended or recycled

If demand cannot be reduced, supplies must be increased, extended or recycled Recycling In USA 60% of lead, 40% of copper, 1/3rd of nickel and almost ¼ of Al, Cr, Co and Zn is recycled Recycled Al requires 20 times less energy than new Al Reduces waste disposal problem

Impact of Mining Activities

Mining Hazards Most hazardous activity in the US: Activity Deaths per 100,000 workers (1989) Mining 43 Agriculture 40 Construction 32

Life Cycle of a Metal Resource Surface mining Metal ore Separation of ore from gangue Smelting Discarding of product Recycling Melting metal Conversion to product Figure 12.7: Life cycle of a metal resource. Each step in this process uses large amounts of energy and produces some pollution and waste. Smelting – heating to release metals but creating air polluting by-products Chemical removal processes such as using cyanide to remove gold can create Toxic holding ponds

Surface Mines Open pit mines Strip mines Where ore body lies close to the surface Leaves a large exposed hole on the surface Exposed rocks prone to weathering and polluting Strip mines Mostly for coal where minerals occur in layers paralleling the surface Waste rocks dumped back as spoil banks Newer regulations require reclamation involving grading, restoring, and replanting Can cause changes in topography and drainage

Extracting Mineral Deposits Surface mining - shallow deposits in US extracts 90% of non-fuel minerals and rocks and 60% of the coal. Overburden – soil and rock overlying deposit. Spoils – discarded overburden Open-pit Mining Area Strip Mining

Mountaintop Removal https://www.youtube.com/watch?v=S16q_x8TUo0&list=PLP7DSVKZyU_19L58grmdHybWKPVn9UGJb

Extracting Mineral Deposits Subsurface mining - deposits that are too deep for surface mining Where does coal come from? https://www.youtube.com/watch?v=1cqzwyg9 fcQ&t=2508s (start at 29:18 – 41:47) https://www.youtube.com/watch?v=ylkdUuNOJzw

Underground Mines Generally less disruptive than surface mines Tunnels closely follow the ore body Some waste rock on the surface Shallow abandoned mines can cause collapse Or worse - https://www.youtube.com/watch?v=v6F0TuV3JMg

99 tons of waste for every ton of Copper https://www.yout ube.com/watch?v =fa6KEwWY9HU

Toxic towns There are many but here is an example http://www.nytimes.com/2012/05/20/magazine/last-ones-left-in-treece-kan-a-toxic-town.html Pics - http://www.businessinsider.com/photos-of-ghost-town-treece-kansas-2015-12 Next year make questions to go with this reading Vid clip - https://www.youtube.com/watch?v=n2wQwIP-tG8

Acid Mine Drainage Homework – read and answer questions for “What the Colorado Waste Water Spill Tells Us About Mining Contamination”

Four PBT Metals PBT: Persistent, Bio-accumulative, Toxic – substances are a class of compounds that have high resistance to degradation (breaking down) and high toxicity. Very long retention times in various media (plants, animals and soil) Widespread distribution across the globe. Majority of PBTs in the environment are either created through industry or are unintentional byproducts. Lead Mercury Cadmium Arsenic

PBT Activity Make a poster and divide that poster in 4 different quadrants Title Definition Each Quad is assigned a PBT (lead, mercury, cadmium, arsenic) For each find the following info Sources (primary source and 1 secondary source) Explain the steps of the process to how it escapes from the source and into the environment The process to which it finds its way into humans (1 primary 1 secondary) The effects of the PBT on humans Draw a diagram that visually traces the path the PBT that you were individually assigned goes from source to humans.

Heavy Metal Contamination & Leaching Heavy metal pollution is caused when such metals as arsenic, cobalt, copper, cadmium, lead, silver and zinc contained in excavated rock or exposed in an underground mine come in contact with water. Metals are leached out and carried downstream as water washes over the rock surface.

Processing Chemicals Pollution occurs when chemical agents (such as cyanide, mercury or sulphuric acid used by mining companies to separate the target mineral from the ore) spill, leak, or leach from the mine site into nearby water bodies. These chemicals can be highly toxic to humans and wildlife. https://www.youtube.com/watch?v=TbI_ZArJ22U (process only) https://www.youtube.com/watch?v=84D6YufrfVo (effects)

Mineral processing and industry has released many of these toxins into the environment. How does it get in you? https://www.youtube.com/watch?v=P5EMAu4H7Ds

Water a little closer to Home Flint Michigan http://time.com/4191864/flint-water-crisis-lead-contaminated- michigan/?iid=sr-link5 Vice – season 4 episode 15 –

Erosion and Sedimentation Mineral development disturbs soil and rock in the course of constructing and maintaining roads, open pits, and waste impoundments. erosion of the exposed earth may carry substantial amounts of sediment into streams, rivers and lakes. Excessive sediment can clog riverbeds and smother watershed vegetation, wildlife habitat and aquatic organisms. https://www.youtube.com/watch?v=1mwryeMqst0

Fig. 12-14, p. 275

Oil and Gas – Black Gold! https://www.youtube.com/watch?v=QtvTE3m5jpM Presenter notes: Oil and Gas are natural resources of enormous economic importance. Together they provide about 60% of all the energy used by society today. They provide fuel for transport and are vital for heating, lighting and cooking. In addition they are used in the manufacture of synthetic fabrics, plastics, fertilizers, detergent as well as for many other purposes. In short, it is hard to imagine how our society could function without oil and gas. Additional background notes for the presenter: It would be useful if the presenter brought along some rock samples as props. These could include an organic rich mudstone (black shale) to illustrate a source rock such as the Kimmeridge Clay (see slide 11), an impermeable rock to illustrate the cap such as halite (see slide 13) and a porous sandstone to illustrate a reservoir rock such as the Penrith Sandstone (see slide 13-14). NASA http://en.wikipedia.org/wiki/Image:Moscow_traffic_congestion.JPG http://upload.wikimedia.org/wikipedia/commons/c/ce/Oil_well.jpg en.wikipedia.org/wiki/Image:Ceratium_hirundinella.jpg en.wikipedia.org/wiki/Image:Oil_platform.jpg

Origin: Chemistry Hydrocarbon Oil and gas are made of a mixture of en.wikipedia.org/wiki/Image:Petroleum.JPG en.wikipedia.org/wiki/Image:Octane_molecule_3D_model.png Hydrocarbon Questions for discussion: What is oil and gas? Where does it come from? Presenter notes: As we begin to think about the origin of oil and gas, a basic question we need to answer is what exactly are oil and gas? Oil and gas are complicated mixtures of different hydrocarbons. A hydrocarbon is a large organic molecule. As the name suggests it is composed of hydrogen atoms attached to a backbone, or chain, of carbon atoms. Short chain hydrocarbons like methane are gases. Medium chain hydrocarbons like paraffin are liquids. Long chain hydrocarbons like bitumen are solids. When crude oil is extracted from the earth it may be a mixture of hydrocarbons in solid, liquid and gas states. Oil and gas are made of a mixture of different hydrocarbons. As the name suggests these are large molecules made up of hydrogen atoms attached to a backbone of carbon. Crude Oil

Origin: Plankton Plant plankton Animal plankton cache.eb.com/eb/image?id=93510 10,000 of these bugs would fit on a pinhead! Plant plankton Animal plankton Presenter notes: It may come as a surprise but most of the world’s oil and gas is made up of the fossil remains of microscopic marine plants and animals. That’s why oil and gas are often referred to as a fossil fuel. One of the most important group of plankton involved in the formation of oil and gas are single-celled marine ‘plants’ called dinoflagellates, though many types of animal plankton are also important. Some oil and gas may have also originated from the remains of land plants, but we will not discuss these types of deposits in this talk. en.wikipedia.org/wiki/Image:Ceratium_hirundinella.jpg en.wikipedia.org/wiki/Image:Copepod. Most oil and gas starts life as microscopic plants and animals that live in the ocean.

Origin: On the sea bed When the plankton dies it rains upload.wikimedia.org/wikipedia/en/0/04/Plankton.jpg When the plankton dies it rains down on sea bed to form an organic mush en.wikipedia.org/wiki/Image:Nerr0328.jpg If there are any animals on the sea bed these will feed on the organic particles Presenter notes: When plankton dies it slowly settles to the sea bed where it forms an organic mush. Usually there are lots of animals living on the sea floor that feed on this material. One important group is the polychaete worms. These are detritivores, which means they eat the dead and decay remains of other organisms Sea bed

Origin: Black Shale However, if there is little or no upload.wikimedia.org/wikipedia/en/0/04/Plankton.jpg However, if there is little or no oxygen in the water then animals can’t survive and the organic mush accumulates Where sediment contains more than 5% organic matter, it eventually forms a rock known as a Black Shale Presenter notes: However, under certain conditions there may be very little oxygen on the sea floor. This may be because the ocean is deep and stagnant and oxygen has not been mixed down from the surface waters. No animal life can survive where the sea bed is completely lacking oxygen. Without animals to eat the dead plankton, the organic mush builds up on the sea bed. Where ocean sediment contains more than 5% organic mush it eventually forms a rock known as a Black Shale. The black colour comes from the dark organic matter that it contains. As we will see, Black Shale is what makes oil and gas. © Earth Science World Image Bank

Origin: Cooking As Black Shale is buried, it is heated. Organic matter is first changed by the increase in temperature into kerogen, which is a solid of hydrocarbon Kerogen Around 90 C, it is changed into a liquid state, which we call oil Presenter notes: As more sediment accumulates on top, layers of Black Shale become buried more and more deeply in the Earth’s crust. As they do so, they slowly heat up because of the geothermal gradient. With progressive heating the organic material in the plankton undergoes chemical and physical changes. It gradually breaks down into smaller and smaller hydrocarbons. At temperatures of around 30°C, a solid, sticky bitumen is produced. Around 90°C liquid oil is formed. As temperatures reach 150°C, natural gases like methane are given off. A Black Shale that is heated and gives off oil and gas is known in the oil industry as a Source Rock. Background notes: This is natural chemical ‘cracking’ of the hydrocarbons – where the initially large molecules are broken into progressively smaller molecules by the increase in temperature – much the same as long chain hydrocarbons can be ‘cracked’ commercially. Oil Around 150°C, it is changed into a gas Gas A rock that has produced oil and gas in this way is known as a Source Rock www.oilandgasgeology.com/oil_gas_window.jpg

Origin: Ancient Earth During mid-Mesozoic times © Ron Blakey, Arizona Flagstaff During mid-Mesozoic times around 150 million years ago, conditions were just right to build up huge thicknesses of Black Shale source rocks The world’s main oil deposits all formed in warm shallow seas where plankton bloomed but bottom waters were deoxygenated Presenter notes: Most of the Source Rocks that gave rise to our present day oil and gas fields were formed in the middle of the Mesozoic Era about 150 million years ago. At that time conditions were just right to build up huge thicknesses of Black Shale. On the one hand, the oceans were unusually warm, promoting vast plankton blooms. On the other hand, oxygen was mostly absent on the ocean floors so most of the plankton that settled on the bottom accumulated. There were no animals around to eat it up. The map on the left hand side shows what the Earth looked like 150 million years ago. The red circles show where the world’s main oil deposits were formed in warm, shallow, deoxygenated seas. Ancient Earth

Origin: Migration Hot oil and gas is less dense than the source rock in which it occurs Oil and gas migrate upwards up through the rock in much the same way that the air bubbles of an underwater diver rise to the surface www.diveco.co.nz/img/gallery/2006/diver_bubbles.jpg Presenter notes: The hot oil and gas does not stay in the Source Rock for long. As the hydrocarbons are less dense than the water in the source rocks that surround them, they gradually migrate upwards through the rock in much the same way that the less dense air bubbles of an underwater diver will rise through water. The migrating oil and gas may travel up through the spaces between the sand grains that make up the rock (called pores) or they may find their way up through cracks, fissures, and faults in the overlying rocks. As we will see when we look at oil exploration, eventually oil and gas get trapped in pockets of rock known as reservoirs. Rising oil The rising oil and gas eventually gets trapped in pockets in the rock called reservoirs

Exploration and Production : Oil Traps Some rocks are permeable and allow oil and gas to freely pass through them Other rocks are impermeable and block the upward passage of oil and gas Where oil and gas rises up into a dome (or anticline) capped by impermeable rocks it can’t escape. This is one type of an Oil Trap. Impermeable Presenter notes: In the first practical we thought about the immense amount of time it takes to form oil and gas. Consequently, it is an extremely valuable resource and huge amounts of money are poured into trying to locate new oil and gas fields. In this section, we will investigate how reservoirs of oil and gas are discovered and how it eventually reaches the marketplace. As we have already seen, once produced, oil and gas migrates out of its Source Rock and accumulates in overlying rocks. Some rocks like sandstone or limestone are permeable to oil and gas, which means that they can pass freely through them. Other rocks like clay or salt are impermeable, which means they block the upward passage of hydrocarbons. One of the most common ways that oil and gas becomes trapped in pockets in the rock is where it is rises into a structural dome capped by impermeable rocks. The cap rocks prevent the oil and gas escaping upwards. The buoyancy of the less dense hydrocarbons in the pore waters prevent them from sinking back down. This is an example of an Oil Trap. Optional exercise: An excellent additional exercise to get students thinking further about how Oil Traps form go to http://earthlearningidea.com, click on Earth-related Activities, and look under the Resource and Environment section. Dome Trap Permeable

Exploration and Production: Seismic Surveys Drill here! Presenter notes: We’ve just established what kind of structures tend to trap oil and gas in the Earth’s crust, but how do we locate potential traps underground? One technique is to use seismic surveys. In this technique, a Vibrator Truck fires shock waves into the ground. The shock waves pass through some rock layers and bounce off others. By recording how long it takes for the shock waves to arrive back at the surface allows geologist to build a picture of the internal structure of the rocks beneath their feet. An example of a seismic survey is shown in the diagram on the right. It reveals a large underground dome in the rocks. As we have seen domes often trap oil and gas so this may be a potential site to drill. Background notes: The term seismic is derived from the Greek for “shake” (think earthquakes!) Earth Science World Image Bank Image #h5inor Earth Science World Image Bank Image #h5inpj Seismic surveys are used to locate likely rock structures underground in which oil and gas might be found Shock waves are fired into the ground. These bounce off layers of rock and reveal any structural domes that might contain oil

Exploration and Production: Drilling the well Once an oil or gas prospect has been identified, a hole is drilled to assess the potential The cost of drilling is very great. On an offshore rig, it may cost $10,000 for each meter drilled. A company incurs vast losses for every “dry hole” drilled Presenter notes: A potential oil trap is called a Prospect. Once a prospect has been identified, the next stage is to drill a hole into the top of the trap to see if it contains oil and gas. It is incredibly expensive to a drill hole. On an offshore rig is may cost $10,000 for every metre drilled. So if you are going to drill a hole 5000 metres underground it’s going to cost you 20 million pounds/ 25 million dollars! Consequently geologists have to be pretty confident that they going to hit oil. If they drill too many ‘dry holes’ they will soon lose their jobs! en.wikipedia.org/wiki/Image:Oil_platform.jpg

Canada’s Tar Sands Higher oil prices and new technology mean unconventional oil deposits are now economically viable (e.g. tar sands) The Athabasca Deposit in Alberta contains 1.75 trillion barrels, or about half of the world’s proven oil reserves! https://www.youtube.com/watch?v=Ro0LWXPlTSA NASA Presenter notes: Whatever the cause of the current rises in oil prices, there is good reason to believe we have not yet reached Hubbert’s era of “peak oil” production. One of the effects of higher prices is that oil deposits that were once considered uneconomic to exploit have now become viable. The largest of the these unconventional oil deposits is the Athabasca tar sands of Albert, Canada. Amazingly this deposit contains over half the world’s oil reserves, equal to 1.75 trillion barrels. The oil is mixed together with sand near the surface and is extracted by opencast mining using giant dumper trucks! However, it is very expensive to extract oil from tar sands, so if this source is used extensively, prices are unlikely to fall. Nevertheless, the Athabasca tar sands together with other probable large oilfields in the Arctic and Antarctica will probably stave of oil shortages for several decades to come.

Politics (9): Global Warming https://www. youtube. com/watch en.wikipedia.org/wiki/Image:Coal_anthracite.jpg en.wikipedia.org/wiki/Image:Bluebbl.gif en.wikipedia.org/wiki/Image:Windpark_Galicia.jpg OIL Presenter notes: Although there probably won’t be an “Oil Crisis” in the short-term, there are other good reasons for investing in alternative sources of power now. The main reason is that oil and gas are a major source of greenhouse gases like carbon dioxide and methane. Together they contribute to global warming which is one of the biggest headaches for modern society to deal with. Oil and gas produce far fewer greenhouse gases than coal per watt of energy produced. However, renewable energy sources like solar, wind and nuclear power are far less polluting. That said, renewable energy has not yet been sufficiently developed to replace fossil fuels as the world’s energy source. In particular it is difficult to develop renewable energy as a source of fuel for transportation. As a result, we will have to live with the environmental consequences of oil and gas for centuries to come – unless we change our habits quickly. Question for discussion after the practical: Apart from fossil fuels what other sources of energy are available? Why are these sources not used more widely? Oil and Gas emit 15-30% less CO2 than coal per watt of energy produced.

Fracking - the process of injecting liquid at high pressure into subterranean rocks, boreholes, etc., so as to force open existing fissures and extract oil or gas. https://www.youtube.com/watch?v=Uti2niW2BRA

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