A Basic Glossary of Iron Ore Mining and Exploration Terms
The information we post on Tsodilo's website and in our press releases regularly uses technical mining terms which may be confusing to non-technical shareholders. Listed below are some brief definitions of some of the more common terms you may see in our written materials.
Assay
A chemical test performed on a rock sample to determine the amount - or grade - of valuable metal contained.
Blast Furnace
A shaft furnace in which solid fuel (coke) is burned with an air blast to smelt ore in a continuous operation.
Bulk sample
A large sample of mineralized rock, frequently hundreds of tonnes, selected in such a manner as to be representative of the potential orebody being sampled. Used to determine metallurgical characteristics on an industrial scale.
Coke
Coke is a solid carbon fuel and carbon source used to melt and reduce iron ore
Cokemaking
The processes used to make coke. The process begins with pulverized, bituminous coal. The coal is fed into a coke oven which is sealed and heated to very high temperatures for 14 to 36 hours. After completion, the coke is moved to quenching towers and stored until it is needed.
Concentrate
A fine product separated in the milling process that contains a high percentage of valuable metal
Concentrator
A process where iron ore is upgraded to a higher iron content.
Crushing
The process of breaking up large rocks into smaller rocks, gravel or rock dust. Crushing is an essential part of the mining, reducing run-of-mine ore to a size that can be easily transported or processed.
Cupola Furnace
Cupola furnaces are tall, cylindrical furnaces used to melt iron and ferro alloys in foundry operations. Alternating layers of metal and ferro alloys, coke, and limestone are fed into the furnace from the top.
Cut-Off Grade
The grade or concentration of metallic minerals below which the material is considered to be uneconomical to mine and process. A cut-off grade of 20% Fe implies that any material containing less than 20% iron will be uneconomical to mine. If the average mine grade drops below the cut-off grade, the mine will operate at a loss.
Dilution
Mixing of ore grade material with non-ore grade waste material in the mining process. Dilution reduces the overall grade of the ore.
Direct-Reduced Iron (DRI)
Produced from the direct reduction of iron ore (in form of lumps, pellets or fines) by a reducing gas produced from natural gas or coal. Direct-reduced iron is richer in iron than pig iron, typically 90-94% total iron, as opposed to about 93% for molten pig iron, and an excellent feedstock for the electric furnaces used by mini mills, allowing them to use lower grades of scrap for the rest of the charge.
Electric Arc Furnaces (EAFs)
Electric arc furnaces are often used in large steel foundries and steel mills. The metal is charged into the furnace, with additives to make recovery of slag easier, and heat to melt the metal is produced with an electric arc from three carbon or granite electrodes. Frequently mills producing steel with EAF technology are called mini-mills.
Energy Optimizing Furnace (EOF)
EOF was developed to replace the electric arc and other steelmaking furnaces. The EOF is an oxygen steelmaking process. Carbon and oxygen react to preheat scrap metal, hot metal and/or pig iron.
Environmental baseline studies
The environmental monitoring work completed before a production decision is taken on a mining project, examining the existing state of the environment and the potential effects that proposed mining activities will have on the natural surroundings. The studies will include ground water (lakes, streams, rivers etc), wildlife (plants and animals), potential noise levels from construction and mining operations, potential impacts from on-going mining operations such as dust and vibration levels etc.
Feasibility Study (Bankable Feasibility Study)
A detailed engineering study which defines the technical, economic, social and legal viability of a mining project with a high degree of reliability, identifying and quantifying any risks and providing sufficient information to determine whether or not the project should be advanced to the final engineering and construction stage. A bankable feasibility study forms the basis on which banks and other lenders provide the capital necessary to build the mine(s).
Fines
Material that passes through a standard screen on which coarser fragments are retained.
Flotation
A concentration process in which valuable mineral particles are induced to attached themselves to bubbles and float away from the waste particles in a solid/solution pulp. Specific chemicals are added to either float (foam off) particular minerals or to depress the flotation of other minerals. Several stages of processing are generally involved with rough bulk flotation products being subjected to additional flotation steps to increase product purity.
Gangue
The worthless minerals in an ore deposit.
Grade
The metal content of ore measured in grams per tonne or percent. For example, a grade of 40% iron implies 400kg of contained iron for each 1,000kg of ore.
Hematite
The mineral form of Iron (III) oxide (Fe2O3), one of several iron oxides.
Induction Furnaces
Induction furnaces are the most widely used type of furnace for melting iron and are increasingly popular for melting non-ferrous metals (USEPA, 1992). They are popular because they provide excellent metallurgical control and are relatively pollution free.
Ironmaking
During ironmaking, iron ore, coke, heated air and limestone or other fluxes are fed into a blast furnace to produce molten iron that is free from impurities.
Iron Ore
Rocks or deposits containing compounds from which iron can be made.
Magnetic Separation
A process in which a magnetically susceptible mineral is separated from waste or undesirable minerals by applying a strong magnetic field; ores of iron are commonly treated in this way.
Magnetite
Fe3O4, Iron Oxide - a dense metallic grey ore mineral of iron.
Metallurgy
The study and practice of removing valuable metals from an ore and refining the extracted raw metals into a purer form.
Mill
A processing plant which crushes and treats ore for the purpose of upgrading the mineral content into a higher grade product called a concentrate, or to produce metal.
Mineralogy
The study of the chemistry and physical properties of ore and gangue minerals within mineral deposits.
Mineral Resource
a concentration or occurrence of natural, solid, inorganic or fossilized organic material in or on the Earth's crust in such form and quantity and of such a grade or quality that it has reasonable prospects for economic extraction. The location, quantity, grade, geological characteristics and continuity of a Mineral Resource are known, estimated or interpreted from specific geological evidence and knowledge.
Mineral Reserve
the economically mineable part of a Measured or Indicated Mineral Resource demonstrated by at least a preliminary feasibility study. This study must include adequate information on mining, processing, metallurgical, economic and other relevant factors that demonstrate, at the time of reporting, that economic extraction can be justified. A Mineral Reserve includes diluting materials and allowances for losses that may occur when the material is mined.
Mini-Mills
Steel production plants that rely on steel scrap as a base material rather than ore. Products do not have the tight chemical composition of integrated plants and have narrower product lines.
Net Smelter Return (NSR)
A royalty payment made by a producer of metals based on gross metal production from the property, less deduction of certain limited costs including smelting, refining, transportation and insurance costs.
NI 43-101 (National Instrument 43-101)
A set of reporting and disclosure standards imposed by regulators on Canadian listed mining and exploration companies that govern how issuers report scientific and technical information about their mineral projects to the public anywhere in the world. It covers oral statements as well as written documents and websites, and it requires that all disclosure be based on advice by a "qualified person".
Ore
A mixture of valuable minerals and gangue minerals from which at least one of the minerals can be extracted at a profit.
Overburden
The alluvium and rock that must be removed in order to expose an ore deposit.
Pellet
A small, round, marble-sized ball of iron ore manufactured as feed for blast furnaces.
Pelletizing
The process by which iron ore is crushed, ground into a powder, rolled into balls and fired in a furnace to produce strong, marble-sized pellets that contain 60% to 65% iron. Raw iron ore pellets are generally manufactured within certain size categories and with mechanical properties high enough to maintain usefulness during the stresses of transference, transport, and use. Both mechanical force and thermal processes are used to produce the correct pellet properties.
Pig Iron
the intermediate product of smelting steel ore with coke and resin. Pig iron has a very high carbon content, typically 3.5 - 4.5%, which makes it very brittle and not useful directly as a material except for limited applications. Pig iron is typically poured directly out of the bottom of the blast furnace through a trough into a ladle car for transfer to the steel plant in liquid form, referred to as hot metal.
Pre-feasibility study
A preliminary assessment of the Economic Viability of a deposit which forms the basis for justifying the completion of a more expensive Feasibility Study. A pre-feasibility study summarizes all geological, engineering, environmental, legal and economic information accumulated to date on the project. The Prefeasibility Study should have error limits of ± 25%.
Qualified Person (QP)
A qualified person (QP) is defined in NI43-101 as an individual who is an engineer or geoscientist with at least five years of experience in mineral exploration, mine development or operation or mineral project assessment, or any combination of these; has experience relevant to the subject matter of the mineral project and the technical report; and is a member in good standing of a professional association. The QP must warrant the accuracy and completeness of a company's technical reports and public disclosures such as press releases or presentations and retains professional responsibility for the contents of the report.
Resource calculation
The mathematical or statistical process of calculating or estimating the amount of material in a mineral deposit, using drill hole information in combination with a variety of geological data. Resources are generally quoted in terms of tonnes of rock present which contain a specified grade of metal(s) e.g. 98-million tonnes at 43% iron.
Scoping Study
The first level of engineering study that is performed on a mineral deposit to determine its economic viability. This is usually performed to determine whether the expense of a full pre-feasibility study and later full feasibility study is warranted. Scoping studies may be completed internally by the Company or by independent engineers.
Sinter
Pieces or granules of fused iron ore.
Sintering
Manufacturing process in which sinter is produced from fine raw iron ore, small coke, sand-sized limestone and numerous other steel plant waste materials that contain some iron. These fine materials are proportioned to obtain a desired product chemistry then mixed together. This raw material mix is then placed on a sintering strand, which is similar to a steel conveyor belt, where it is ignited by gas fired furnace and fused by the heat from the coke fines into larger size pieces that are from 0.5 to 2.0 inches.
Slag
Impurities in the iron ore that have been captured by limestone or other fluxes.
Steel
Steel is an alloy of iron usually containing less than 1% carbon which is used most frequently in the automotive and construction industries or is cast into bars, strips, sheets, nails, spikes, wire, rods or pipes as needed by the intended user.
Strip Ratio
The ratio of tons of overburden waste material to tons of ore in an open pit mine.
Tailings
Crushed or finely ground waste rock from which valuable minerals or metals have been extracted.
Thermal processing
To confer to iron ore pellets high resistance metallurgic mechanics and appropriate characteristics, the pellets are subjected to thermal processing, which involves stages of drying, daily pay burn, burn, after-burn and cooling (in a cooling tower). The duration of each stage and the temperature that the pellets are subjected to have a strong influence on the final product quality.
Waste
Barren rock or mineralized material that is too low in grade to be economically processed
