A worksheet produced by the Native Access to Engineering ProgrammeConcordia University, Montreal

Worksheet 12

Mining

Teacher’s Guide

Here are some suggestions for how you can work with Worksheet 12, Mining.

1. VocabularyAfter reading this worksheet, your students should understand thefollowing terms:

Acidic drainage Ore depositsBlasting Pit miningDrift Probe HolesDrilling ProspectingGeologist QuarryHauling Reclamation planIgneous Rock ScalingLoading Sedimentary rockMine ShaftMineral Strip miningMetamorphic rock TailingsNative elements Trenching

2. Do your students understand the definition? Can they explain in their own words what mining is?

3. For more information about the periodic table and chemistry see Chemistry, worksheet 5, available onlineat http://www.nativeaccess.com/Worksheets/worksheet5/worksheet-5-1.htm.

4. A list of a few of the 3,000 or so identifiable minerals your students might name follows. Can they give youone mineral for each letter of the alphabet? If they need help, a fairly comprehensive alphabetical list canbe found at http://www.minerals.net/mineral/sort-met.hod/alphabet/abcdsort.htm. This site also providesadditional information about each mineral including hardness, colour, abundance, and chemical composition.

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Agate Cuprite Jade Obsidian SodaliteAlabaster Diamond Jasper Onyx SulfurAmethyst Emerald Kernite Opal TalcAntimony Feldspar Lead Pitchblende TopazAquamarine Fluorite Lapis-Lazuli Platinum TurquoiseBauxite Galena Magnetite Pyrite UraniniteBismuth Garnet Malachite Quartz VesuvianiteBloodstone Gold Marble Rhodonite WitheriteBornite Graphite Marcasite Ruby XenotimeCalcite Gypsum Mercury Serpentine YugawaraliteChromite Hematite Moonstone Silver ZirconCopper Iron Nickel

5. The answer to this question will vary depending on the area in which you live. Below is a list of minerals(and other resources) which are mined in each province and territory. Regional descriptions of miningactivity can be found at the Natural Resources Canada’s web site www.nrcan.gc.ca/ms/efab/mmsd/facts/default.html

Newfoundland and Labrador: Iron, GoldNova Scotia: Coal, Gypsum, SaltNew Brunswick: Zinc, Potash, Silver, Lead, Peat, Copper, CoalQuebec: Gold, Zinc, Iron, Asbestos, Copper, Granite, TitaniumOntario: Nickel, Copper, Gold, Sand, Gravel, StoneManitoba: Nickel, Copper, Zinc, Gold, Sand, GravelSaskatchewan: Uranium, PotashAlberta: CoalBritish Columbia: Indium, Molybdenum, Gold, Copper, SilverYukon: Gold, Zinc, Lead, Silver, Sand, GravelNorthwest Territories: Lead, Zinc, Gold, DiamondsNunavut: Zinc, Lead, Gold

6. More information about rock types, obtained from http://jersey.uoregon.edu/~mstrick/AskGeoMan/geoQuerry13.html.

Igneous: Igneous rocks are crystalline solids which form directly fromthe cooling of magma. This is an exothermic process (it loses heat) andinvolves a phase change from the liquid to the solid state. The earth ismade of igneous rock – at least at the surface where our planet is to thecoldness of space. Igneous rocks are given names based upon two things:composition (what they are made of) and texture (how big the crystalsare). Basalt and granite are two types of igneous rock.

Sedimentary: In most places on the surface of the Earth, the igneousrocks which make up the majority of the crust are covered by a thinveneer of loose sediment, the rock which is made as layers of this debrisget compacted and cemented together. Sedimentary rocks are calledsecondary, because they are often the result of the accumulation ofsmall pieces broken off of pre-existing rocks. There are three main typesof sedimentary rocks:

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Clastic: your basic sedimentary rock. Clastic sedimentary rocks are accumulations of clasts: little pieces ofbroken up rock which have piled up and been “lithified” by compaction and cementation.Chemical: many of these form when standing water evaporates, leaving dissolved minerals behind. These arevery common in arid lands, where seasonal “playa lakes” occur in closed depressions. Thick deposits of salt andgypsum can form due to repeated flooding and evaporation over long periods of time.Organic: any accumulation of sedimentary debris caused by organic processes. Many animals use calcium forshells, bones and teeth. These bits of calcium can pile up on the seafloor and accumulate into a thick enoughlayer to form an “organic” sedimentary rock.Examples of sedimentary rock are sandstone, limestone and shale.

Metamorphic: The metamorphics get their name from “meta” (change) and “morph” (form). Any rock canbecome a metamorphic rock. All that is required is for the rock to be moved into an environment in which theminerals which make up the rock become unstable and out of equilibrium with the new environmental conditions.In most cases, this involves burial which leads to a rise in temperature and pressure. The metamorphic changesin the minerals always move in a direction designed to restore equilibrium. Common metamorphic rocksinclude slate, schist, gneiss, and marble.

7. This question is intended to make students think about a process. If there is a desirable mineral in seawater, or under the ocean floor what would be the challenges of getting at it?

The ocean has an abundance of minerals but is mined very little as most minerals are more easilyacquired on land. Marine mining can place on a number of levels: the beach, the shallows ofcontinental shelves and the deep ocean (including the ocean floor). Different minerals are found ineach area. Challenges to marine mining will depend on what level you are mining and what mineralsyou are trying to obtain. Below is list of some challenges you might face in marine mining.

• How to get minerals out of the water. Some minerals will be suspended in seawater. How wouldyou filter them out in a way that is cost effective?

• Depth. There may be large mineral deposits in very deep water. Going deep means being able towithstand great pressures. What kind of equipment will be needed to meet these challenges?

• Tides. On beach level and in shallows, tides would have to be taken into consideration. Not onlywould timing of activities be affected by change in water depths, but equipment used would needto be able to withstand the force of huge volumes of moving water.

• Shore and Marine wildlife and plant life protection. Howwill activities effect plants and animals? What measureswill be required in order to ensure their safety?

8. Mining underground.

Advantages:• Only ore is mined, whereas in open pit or strip mining there areoften several tons of waste stripped for each ton of ore• With care there is less direct damage to ecosystems

Disadvantages:• The costs, which for each ton of material mined, are much higherunderground than on the surface.• Access is much more limited.• It may require more time to mine the ore.

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9. This question is regionally specific.

A number of First Nations have historically practiced mining of materials close to the earth’s surface. In NorthAmerica copper was the primary element mined as it is very abundant all over the continent. Mined metal wasused for tools (knives etc.) decorative objects and plates. Perhaps an elder or community member familiar withhistory and traditional practices can be invited to address the class.

10. There are a number of well-known and well-documented instances of disagreements concerning mineralrights on First Nations’ territory in Canada and other countries. It would perhaps make an interestingresearch project for your class to look at one of these cases (perhaps Voisey’s Bay) so that they develop adeeper understanding why knowledge of mining, mineral resources and local geography could be importantfor a community.

11. The history of the earth can tell us a lot about where we might potentially find certain types of minerals.For instance:

• Coal deposits are found in areas where ancient forests once stood.• Certain minerals are very rare on Earth itself, but not so rare in asteroids and meters which occasionally

impact the planet. Knowing where (and when) impact craters have occurred can lead miningengineers to deposits of rare minerals and metals.

• Certain kinds of metamorphic rock and minerals will only be found in places where great pressurebetween continental plates or high temperatures from volcanic activity have existed.

12. The answer to this question is contained in the paragraph whichfollows.

13. For an activity to be profitable it must generate more money thanit requires to function. In mining operations, companies aregenerally looking for large profits; if the profits aren’t large enough,chances are the resource will not be tapped.

In order for a mine to be profitable, it must produce enough ore toconsiderably exceed the cost of salaries, infrastructure and operation.Productivity (the amount of ore produced per a specified nit of time)must be reasonably high. Mining companies also have to take intoconsideration the market value of their ore. Minerals prices can behighly volatile (the high price for gold in 1972 was 70US$ per troyounce, in 1980 it was 850US$ per troy ounce) so over the course of 6months, over several years a mine may go from being profitable tobeing unprofitable. In some cases, companies will close mines if theprice of ore drops and reopen them when the ore price climbs back up.

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14. Abandoned mining towns are often referred to as ghost towns. In many, the buildings were abandoned asis and may still be standing today, giving the impression the town is inhabited by ghosts.

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15. Safety concerns:Sufficient ventilation; proper safety equipment (hard hats, gloves etc.); supportof underground structures to prevent cave-in; proper use of heavy equipment,chemicals and explosives

Environmental concerns:Proper disposal of chemicals and waste products; understanding of local wildlife and plant life; care of the land (especially in delicate environments)

16. The chemical equation representing the materials used in mine blasting is

3NH4NO + CH4 Õ CO2 + 7H2O + 3N2 + heat.

In other words, blasting produces carbon dioxide, water, nitrogen gas and heat.It is important to know what products (and how much of each) are going to beproduced by this reaction, in order to determine whether it is safe for thepeople working in the mine. The reaction of ammonium nitrate and fuel oilproduces products generally found in the air we breathe.

17. Scaling is important for safety. Loose rocks must be removed inorder that they do not fall and injure mine workers.

18. Ventilation may also be required in order for mine machinery towork. Machines using internal combustion engines require theoxygen provided through ventilation in order to function.

19. Acidic drainage from mines can raise the acidity of local soil andwater. High acid levels may over time kill off or increase diseaselevels in certain species affecting local food chains. Ultimately,hunters and fishers may find that the game they have traditionallysought no longer exists, is severely depleted or can no longer beeaten.

20. Cyanide can be produced by certain bacteria, fungi, and algae, and it isfound in a number of foods and plants. In the body, cyanide combineswith a chemical to form Vitamin B12. Cyanide occurs naturally in a numberof plant roots including cassava roots, which are potato-like tubers ofcassava plants grown in tropical countries. Cyanide is usually found joinedwith other chemicals to form compounds. Examples of simple cyanidecompounds are hydrogen cyanide, sodium cyanide and potassium cyanide.At high concentrations, cyanide becomes toxic to soil microorganisms andcan pass through soil into underground water. Cyanide is a very poisonouschemical. Exposure to high levels of cyanide harms the brain and heart,and may cause coma and death. Exposure to lower levels may result inbreathing difficulties, heart pains, vomiting, blood changes, headaches,and enlargement of the thyroid gland.

21. The answers to both questions will depend on what the students see anduse everyday, however here are some metals and minerals found in dailylife: Tin (appliances); Nickel (coinage); Aluminum (vehicles); Steel(buildings, vehicles); Silicon (computers, electronic devices); Salt, Goldand Silver (dental work, jewelry); Copper (roofing, cooking utensils).

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Solutions

Problem 1: MappingYour students will require graph paper in order to do this exercise.

I. What do you know?• 10m between probe holes• Depths of gold at each hole (from table)

II. AssumptionsIn some ways this problem is a little challenging because the students arebeing asked to map a “theoretical” three-dimensional section. The coordinatesgiven only truly define what is found directly underneath them; a logicalguess or assumption will have to be made about what happens in between theprobe holes. Engineers are required to make assumptions like this as a regularpart of their work.

If the students look carefully at the given figure, what can they conclude? Essentially, the given points can be usedto describe two parallel, vertical planes, running East-West (or 4 running North-South). A good assumption tomake would be that in each plane a point can be connected to the points horizontally or vertically adjacent to itby a straight line. What will this line estimate? The change in depth of the gold ore between two known points.

There are a number of ways to come to a solution. The one provided here maps one plane, then the other and finallyjoins them together to produce a rough map of the prospected gold ore.

III. Layout probe holes 1-4

a) Decide on scale.The scale used here is 1 square = 2m.

b) Layout the probe holes (Step 1).

IV. Draw in what is known about holes 1-4.Insert lines which show the depth of the gold ore at eachprobe hole.(Step 2)

Step 1

Step 2

V. Join the tops and bottoms of each hole together in order to create plane1. (Step 3)

VI. Layout probe holes 5-8. (Step 4)Before the students layout the probe holes 5-8, they need to rememberthey are working in three-dimensions. If they want to see the shape of theore deposit they will need to skew holes 5-8 on an angle from hole 1-4. Inlaying out the first plane, the scale 1 square equals 2m was used. Onregular graph paper using a 30° or 45° diagonal, this scale may not resultin the new probe hole line landing plumb on a line. If the students find iteasier, they can lay the probe holes on a line at a diagonal angle whichapproximates the scale they have chosen, maintenance of the vertical scaleis more important than accuracy on the diagonal.

VI. Draw in what is known about probe holes 5-8. (Step 5)Insert lines which show the depth of the gold ore at each probe hole.Students should be careful to measure from the correct probe hole.

VIII. Join the tops and bottoms of the new line plots together toform plane 2. (Step 6)

Step 3

Step 4

Step 5 Step 6

Step 7

IX. Create the three-dimensional map.Students should now have two parallel planes – which might be easier todistinguish if they are shaded in different colours. To complete thethree dimensional map, they should draw lines between the planes, i.e.,between the tops and bottoms of the lines for points 1 and 5, 2 and 6, 3and 7, 4 and 8. (Step 7)

AnswerFrom the map the students should be able to make anumber of conclusions including:• The gold deposit seems to increase towards the

North and decrease towards the South, so moreexploration should be undertaken in towards theNorth

• In general, the gold deposit seems to be largertowards the east, although exploration to both theeast and west in line with the first plane areprobably warranted.

• The gold deposit is not too far below the surface,surface mining may be viable. Enlarged map

Problem 2. Percentages and calculation

I. What do you know?• 1500 tonnes of iron ore mined per day• mined material is 43% waste• steel beams 1000kg each• each beam requires 1080kg raw iron

II. Convert tonnes to kilograms1500 tonnes x 1000kg = 1,500,000kg

tonne

III. Determine how much usable ore is produced per day

If 43% of the mined material is waste 100-43, or 57% is usable material.

Iron ore/day = 0.57 x 1,5000,000kg/day= 855,000kg/day

IV. Determine the number of beams made from daily production at the mine

# of beams = total iron ore for one day/iron ore required per beam = 855,000kg x 1 beam

1080 kg

= 791.67 beams

Since you really can’t make 0.67 of a beam, the answer should be rounded down to 791 beams.

Answer: 791 beams