HW3-Mineral Uses ^0 Consumption_Hoffman_70

MINERAL USES AND CONSUMPTION OBJECTIVES:  Familiarization and practice with basic equations about mineral mining, ore grade, and waste rock production  Familiarization with market trends for metal commodities. INTRODUCTION Throughout human history, societies have been built upon Earth’s rock and mineral resources. Indeed, our names for notable periods of human history – Stone Age, Bronze Age, and Iron Age – identify the prevailing resources used during that period. What would be an appropriate name for our present period? One hundred years ago, people created materials from only 20 of the naturally occurring chemical elements (iron, silicon, oxygen, silver, etc.). Today, we use most of the 92 naturally occurring elements to produce the machinery, tools, and goods used daily throughout our society. Population growth, an improved global standard of living, and a technologically advanced society, contribute to a greatly increased demand for natural resources. While the demand for many mineral resources increases, a growing number of obstacles have begun to reduce the availability of these resources. Two political obstacles that affect mineral development are the competing uses for available land and concern about environmental degradation. Other factors, such as natural abundance and ease of mineral extraction, also affect the availability of mineral resources. Natural abundance, market demand, and the environmental impact of mineral extraction are all important factors in determining a mineral’s role in our daily life and society. In this activity, you will consider one mineral resource (copper) and learn about its degree of concentration in Earth’s crust, calculate how much rock has to be mined to extract the mineral resource, and examine the relationship between its price and production. ASSIGNMENT What minerals contain copper? Copper is a base metal. The term “base” refers to all no precious metals and dates back to the time of alchemists, who considered every metal except gold to be common or “base.” Copper constitutes 0.0057% of Earth’s crust by weight. The copper that we mine typically occurs in a variety of minerals. 1. List 5 copper-bearing minerals and their chemical formulae. (1) Chalcopyrite - CuFeS2 (2) Bornite – Cu 5 FeS 4 (3) Malachite – Cu2co3 (0H)2 (4) Chalcocite – Cu2S (5) Covellite – Cu x S y Most copper that we mine comes in the form of a mineral called chalcopyrite (CuFeS 2 ). To recover the copper, we must first mine rock that contains chalcopyrite, then separate the chalcopyrite from the rock, and finally break the bonds that hold the copper, iron, and sulfur together to remove the copper. MINERAL USES & CONSUMPTION - 1

How much copper is in chalcopyrite? 2. To find out how much elemental copper is in chalcopyrite, we calculate the formula weight percent. Use the following table to calculate the formula weight of chalcopyrite. CuFeS 2 ELEMENT ATOMIC MASS UNIT (g/mol) NUMBER OF ATOMS TOTAL MASS (g/mol) Cu 63.54 1 63.54 Fe 55.85 26 = 26.00 =14.52 14.52 S 32.06 16 = 16.00 = 51.29 51.29 Sum (∑) = 129.35 Note: units are shown as g/mol (grams / mol), where a mole = 6.02 x 10 23 atoms. 3. Calculate the percentage of copper in chalcopyrite. [(34.63) / (129.35)] x 100 = 26.77 4. In a typical copper deposit in Arizona, approximately 14 kilograms of chalcopyrite is contained in every metric ton (approximately 1000 kilograms of rock mined). How much copper is contained in 1 metric ton of mined rock? (Round your answer to the nearest kilogram.) (14 kg of chalcopyrite) x (26.77 / 100) = 3.74 kg What’s left over? 5. How much waste rock is produced by a copper mine for every metric ton of rock mined? (3.74) – (1000) x -1- = 996 kg Richness of the ore 6. The ore grade of the deposit is the relative quantity or percentage of ore mineral content in a deposit. What is the ore grade (sometimes called percent grade) of this Arizona deposit? [(mass of copper in 1000 kg of rock) / (1000 kg of rock)] x 100 = 10,000 7. Compare the grade that you calculated above to the average amount of copper distributed in the Earth’s crust. Copper in Arizona has been geologically concentrated into an ore body. An ore body is any mineral resource that can be extracted, refined, transported, and sold at a profit. What is the concentration factor in a typical Arizona copper deposit? Solve for the concentration factor in the equation below. (percentage in crust 996 ) x (concentration factor 10,000) = (percent grade of ore 99.60 * 100 =99.60) Concentration factor = 99% (Round your answer to the nearest hundred) 8. Chile produces approximately 30% of the world’s copper, whereas the United States produces less than 18%. A typical copper ore grade in Chile is 1%. How many kilograms of copper are extracted from a metric ton of rock in a Chilean mine? MINERAL USES & CONSUMPTION - 2

11. Like many other commodities, the price of copper has varied through time. Examine the 60-year history of copper prices below. Describe the change in copper prices between 1960 and 2020. The copper price went up from below $.50 in 1960 and in 2020 copper rose to $3.00. The highest that sales of copper got up to was between 2010 and 2020 at $4.50. Source: www.macrotrends.net/1476/copper-prices-historical-chart-data ; Copper Prices - 45 Year Historical Chart | MacroTrends . 12. Consider what you know about copper and its uses and offer a possible explanation for the 60-year price change. Copper, a remarkably versatile metal, finds extensive application across a wide range of industries, including construction, electronics, and transportation. Its exceptional electrical conductivity, corrosion resistance, and malleability render it highly esteemed. Over the past six decades, the price of copper has experienced significant fluctuations, a phenomenon that can be attributed to the intricate interplay between supply and demand factors. The demand for copper, in turn, can be influenced by a multitude of factors, such as the prevailing global economic conditions, the advent of groundbreaking technological advancements, and the shifting landscape of industrial production. Moreover, the supply of copper can be subject to MINERAL USES & CONSUMPTION - 4

the sway of geopolitical considerations, trade policies, and the inherent volatility of mining production. It is the intricate interplay of these multifaceted dynamics that gives rise to the volatility observed in copper prices over time. U S primary copper production 1900–2008. Source: USGS 13. Above is a diagram showing Copper production and value statistics for the United States from 1900- 2008 (I couldn’t find an updated diagram!). Select the sentence that best describes the overall relationship between price and production for copper using these data. a. There is a general direct relationship between price and production. b. There is a general inverse relationship between price and production. c. There is no noticeable relationship between price and production. 14. U.S. consumption of copper is approximately 2.95 million metric tons per year. Divide this by the current population (333 million; 2022 U.S. Census Bureau) to determine your usage. MINERAL USES & CONSUMPTION - 5

Acknowledgment Portions of this lab exercise were reproduced from: Poulton, M.M. (2004). Mineral use and consumption, EarthInquiry Investigations, http://www.earthinquiry.com . MINERAL USES & CONSUMPTION - 7