MINERAL DEPOSITS HOW, WHERE, WHEN, AND WHY HERE Jim Miller, University of Minnesota Duluth
MINERAL DEPOSIT IQ TEST 1) What is the main use for Nickel? Stainless Steel
MINERAL DEPOSIT IQ TEST 2) What is the main use quartz (silica) sand? Glass-making
MINERAL DEPOSIT IQ TEST 3) What is the main use for palladium? Catalytic Converters
MINERAL DEPOSIT IQ TEST 4) What country is referred to as the “Jewelbox of the World”? South Africa
MINERAL DEPOSIT IQ TEST 5) What is the principal commodity needed to make Rayon, Polyester and other synthetic fabrics? Petroleum
MINERAL DEPOSIT IQ TEST 6) What is the only thing in this room that is not grown on or mined from the Earth? Sunlight
MINERAL DEPOSIT IQ TEST 7) How much copper is in a medium- sized wind turbine? A) 15,000 lbs B) 9,000 lbs C) 6,500 lbs D) 2,000 lbs E) 400 lbs
MINERAL DEPOSIT IQ TEST 8) Chile produces the most (1/3 rd ) of the world’s copper; which country is the second largest producer of copper at 8%? United States
MINERAL DEPOSIT IQ TEST 9) What is the average percentage of platinum in the Merensky Reef deposit of South Africa ? A) 10% B) 1% C) 0.1% D) 0.01% E) %
MINERAL DEPOSIT IQ TEST 10) What percentage of mineral deposit prospects become mines? A) 50% B) 10% C) 5% D) 1% E) 0.1%
Terminology and Definitions Biological Resources renewable recycleable reuseable Mineral Resources non-renewable recycleable reuseable Water Resources unlimited recycleable reuseable Wind and Solar unlimited “Sustainable Development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs” (1984, United Nations Commission) Stewardship - “administration, management, control, including responsible use of resources” (Oxford English Dictionary Online) Natural Resources – materials, and energy that occur naturally within the Earth’s spheres. Many are essential for our survival, while others are used for satisfying our wants. Stuff
Mineral Deposit Terminology Ore – rock whose value of metals exceeds the cost of extracting them by mining and processing Grade – percentage of a particular metal in ore rock Prospect – a mineral occurrence that preliminary investigations indicate a possibility of a significant resource Resource – tonnage of ore in such form, quality and quantity that there are reasonable prospects for eventual economic extraction Inferred Resource is that part of a mineral resource for which tonnage, grade and mineral content can be estimated with a low level of confidence. Indicated Resources are economic mineral occurrences that have been sampled to a point where reasonably confident estimate can be made of their contained metal, grade, tonnage, shape and physical characteristics Reserves - are resources known to be economically feasible for extraction.
How? Most rocks on earth contain some amount of metals, but metal concentrations are so low (parts per billion - ppb), as to not be considered ORE. Ore deposits form in under special geological circumstances and processes whereby metals are concentrated to economic grades. Economic concentrations of metals are created by primary processes (those related to the rock in which they occur) and secondary processes (those unrelated to the origin of the host rock). In most ore deposits, sulfur &/or oxygen are the main anions (- charged ions) that concentrate metal cations; other metal- bonding anions include As, Bi, Te, CO 3, Cl, …
How?
Chalcopyrite CuFeS 2 Bornite Cu 5 FeS 4 Cobaltite CoAsS Sphalerite ZnS Galena PbS Chalcocite Cu 2 S Molybdenite MoS 2 Pentlandite (Fe,Ni) 9 S 8 Cinnabar HgS How? Most Base Metals are concentrated by Sulfur
HOW? Formation of PGE deposits by sulfide liquation
HOW? Sulfur Contamination creating the Cu-Ni-PGE Sulfide Deposits of the Duluth Complex S Cu Ni Co Pd + Pt + Au S
HOW? New Processing Technology for Sulfide Ores OLD – Smelting/ Roasting NEW – Hydrometallurgy with High Pressure Autoclaves
HOW? The Challenge – Acid Rock Drainage 2FeS 2 (s) + 7O 2 (g) + 2H 2 O(l) → 2Fe 2+ (aq) + 4SO 4 2- (aq) + 4H + (aq)
Where?
Buried too Deep Just Buried Where/When?
When? Archean Komatiite Flows with Ni-sulfide Mineralization Evidence of an Early Hot Mantle
Inconvenient Truth #3 When? Archean Paleo-placer U deposits Evidence of an Anoxic Atmosphere
Inconvenient Truth #3 When? Porphyry Cu Deposits preserved in young mountain belts
Peat Anthracite Bituminous Coal Anthracite Coal When? Land plants take root on land about 350 Ma COAL!
Inconvenient Truth #3 When? Porphyry Cu Deposits preserved in young mountain belts gone
Inconvenient Truth #3 Why Here?
Inconvenient Truth #3 Why Here?
BECAUSE MOTHER EARTH SAID SO! Why Here?
Mineral Resource Information US Geological Survey Commodity Information US Geological Survey Mineral Resource Database Minerals Education Coalition Society of Mining, Metallurgy and Exploration (SME) Prospectors and Developers Association of Canada (PDAC) – Mining Matters Educational Initiative
Lesson Plan Ideas for Mineral Deposits How to make a lightbulb? Objective: An important element in promoting stewardship of our earth resources is to educate students about what earth resources are involved in the making of everyday things. We will use manufacturing of a lightbulb to illustrate this point. Exercise: You are an environmentally conscientious entrepreneur who want to build a compact fluorescent lightbulb factory in Minnesota. One of the most important decisions is to figure out what materials you need and where to get them. Cost is a function of distance and the country supplying the material. Third world countries provide cheaper prices, but are notorious for poor environmental standards in mining and low wages. Procedure: You will be assigned an earth resource that is needed to manufacture a CFL light bulb. Using the USGS and MII websites, research the following information on your assigned resource. Geologic occurrence (host rock, geological environment) Enrichment process (primary or secondary?) Age of occurrence Imports (% of US consumption) Alternative Materials Other interesting Information