1. Mineral Deposits 1 - Introduction I.G.Kenyon

2. Mineral Deposits – Basic Terminology 1 Mineral – something that can be mined from the ground and is of economic/industrial value 294.10 Troy Ounces 61 lb 11oz!

3. Mineral Deposits – Basic Terminology 2 Ore – the valuable material extracted Comprises the Ore mineral and the Gangue Ore Mineral – the mineral from which the valuable component usually a metal will be derived Chalcopyrite, Bornite, Azurite, Chalcocite and Malachite are all mined to extract Copper

4. Mineral Deposits – Basic Terminology 2 Gangue – the unwanted part of the ore, comprises minerals such as calcite, quartz and iron pyrite

5. Mineral Deposits – Basic Terminology 3 Grade – Refers to the proportion of the ore that is the ore mineral or actual elemental metal content that can be extracted from it - expressed as a percentage The grade of the Cornish tin ore is between 0.5 and 1.5 % cassiterite (Sn O 2 ) This means there is between 98.5 and 99.5% gangue in the ore

6. Mineral Deposits – Basic Terminology 4 Tenor – Refers to the percentage of the ore mineral that is actual metal to be extracted The tenor of iron ores vary considerably: Limonite 35% Fe, Haematite 57% Fe, Magnetite 70%

7. Calculating Ore Grade as % Mineral Content and % Elemental Metal Content Using Chalcopyrite as an example: Chemical Formula is Cu, Fe, S 2 Relative atomic masses are: Cu = 63.5, Fe = 56 and S = 32 So 1kg of copper will be found in: 63.5 + 56 + (2 x 32)/63.5 This equals 2.9 kg of Chalcopyrite If the ore contained 2% copper then it would have 2 x 2.9 = 5.8% Chalcopyrite

8. Calculating Ore Grade as % Mineral Content and % Elemental Metal Content If the process is reversed: The grade of the ore as metal content can be calculated 100% Cu, Fe, S 2 contains 63.5/63.5 + 56 + (2 x 32) x 100 = 34.6% Cu Metal Ore of 2% Chalcopyrite contains: 34.6 x 2/100 = 0.692% copper metal

9. Mineral Deposits – Basic Terminology 5 Tonnage – Refers to the total amount of metal that can be extracted from any particular ore deposit. Tonnage is calculated by taking into account the volume of the ore deposit, the grade of the ore and the tenor of the ore mineral

10. Syngenetic – A mineral deposit formed at the same time as the enclosing rock Classification of Mineral Deposits 1 Example:Grains of tin that form part of the matrix in a river bed conglomerate

11. Epigenetic – A mineral deposit formed later than (after) the enclosing rock Classification of Mineral Deposits 2 Example:Tin and Copper in Cornwall introduced into the country rock or ‘killas’ (of Devonian age) by hydrothermal fluids, following later granite emplacement (End of Carboniferous)

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