Geological processes create two basic types of diamond deposits, referred to as primary and secondary deposits. Primary sources are kimberlite and lamproite pipes that raise diamonds from the Earth's mantle where they originate. Secondary, or placer, sources, created primarily by alluvial erosion, include such deposits as surface scatterings around pipes, concentrations in river channels, and fluxes from rivers moved by wave action along ocean coasts. Secondary deposits may be found far from active means of transport, in the fossilised channels of ancient rivers or under fossil beaches. Mining of these deposits depends upon sufficient concentration and quality of diamonds.
Kimberlites are igneous rock matrixes composed of carbonate, garnet, olivine, phlogopite, pyroxene,serpentine, and upper mantle rock, with a variety of trace minerals. They are found as dykes andvolcanic pipes, which are the source of rare and relatively small volcanoes. Kimberlite pipes are the most significant primary source of diamonds, yet only about one in every 200 kimberlite pipes is diamondiferous.
The location of alluvial (or placer) diamond deposits is controlled by the surrounding topography. Alluvial diamond deposits are usually located within river terrace gravels that have been transported from their location of origin, usually from kimberlite deposits,and deposited in a lower-energy meandering or braided stream environment.
Alluvial Diamond deposits which are located in sediments transported by river or marine systems.
Audit Checking mechanisms to verify the veracity of results.
Barren Kimberlite which does not contain diamonds.
Basalt A fine-grained basic igneous rock which is erupted through volcanic activity.
Bulk sample Large sample which is processed through a small-scale plant, not a laboratory.
Calcite A carbonate mineral with the chemical formula, CaCO3.
Calcrete A carbonate cement formed in soils during diagenesis, typically in stable semi-arid climate areas.
CAPEX Capital expenditure.
Carat Unit of weight for diamonds. The metric carat equals 200 mg.
Chrome-diopside One of the clinopyroxene group of minerals, commonly found in igneous rocks.
The chrome end-member of the group often found in kimberlites.
Cross section A diagram or drawing that shows features transected by a vertical plane drawn at right angles to the longer axis of a geologic feature.
Cut-off grade The lowest grade of mineralised material considered economic to extract; used in the calculation of the ore reserves in a given deposit.
Diamond drilling A drilling method, where the rock is cut with a diamond bit, to extract a core of the rock.
Diamond grade The content of diamonds, measured in carats, within a volume or mass of rock.
Diamond value The estimated average value of diamonds from the deposit, quoted in US$/carat.
Diamondiferous Containing diamonds.
Dilution Waste which is mixed with ore in the mining process.
DMS Dense Medium Separation, a way of separating diamonds or heavy minerals from waste material using a
flotation process.
Dolerite A medium-grained igneous rock which is emplaced within the earth's crust in the form of dykes and sills, and has the same mineralogy as basalt.
Dyke Intrusive igneous rock vertically or subvertically emplaced.
Estimation The quantitative judgement of a variable.
Exploration Prospecting, sampling, mapping, diamond drilling and other work involved in the search for mineralisation.
Feasibility study A definitive engineering estimate of all costs, revenues, equipment requirements and production levels likely to be achieved if a mine is developed. The study is used to define the economic viability of a project and to support the search for project financing.
Fresh rock Hard rock, at depth beneath the earth, which has not been subjected to the processes of weathering.
Garnet A silicate mineral. The magnesium-rich variety, pyrope, is commonly found in kimberlites.
Geomorphological Geomorphology is the study of land-forming processes, known as geomorphological processes.
Grade The relative quantity or percentage of diamonds within the rock mass. Measured as carats per hundred tonnes in this report.
Gravity survey A geophysical study undertaken from the surface or from the air which identifies variations in the density of the earth from surface to depth.
Igneous Rocks resulting from the crystallisation of a molten magma, either intrusive or volcanic.
In situ In its original place, most often used to refer to the location of the mineral resources.
Indicated Diamond Resource That part of a diamond resource for which tonnage, densities, shape, physical characteristics, grade and average diamond value can be estimated with a reasonable level of confidence. It is based on exploration sampling and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes. The locations are too widely or inappropriately spaced to confirm geological and/or grade continuity but are spaced closely enough for continuity to be assumed and sufficient diamonds have been recovered to allow a confident estimate of average diamond value (SAMREC Code).
Inferred Diamond Resource That part of a diamond resource for which tonnage, grade and average diamond value can be estimated with a low level of confidence. It is inferred from geological evidence and assumed but not verified by geological and/or grade continuity and a sufficiently large diamond parcel is not available to ensure reasonable representation of the diamond assortment. It is based on information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that may be limited or of uncertain quality and reliability (SAMREC Code).
JSE JSE Limited.
Kimberlite An ultra basic rock defined as a porphyritic alkalic peridotite containing phenocrysts of olivine and
phlogopite. Occurs as dykes or as characteristically carrot-shaped pipes.
Matrix Fine grained rock which supports larger clasts or pebbles.
Measured Diamond Resource A “Measured Diamond Resource" is that part of a diamond resource for which tonnage, densities, shape, physical characteristics, grade and average diamond value can be estimated with a high level of confidence. It is based on detailed and reliable exploration sampling and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes. The locations are spaced closely enough to confirm geological and grade continuity and sufficient
diamonds have been recovered to allow a confident estimate of average diamond value.
Mineable That portion of a resource for which extraction is technically and economically feasible.
Mineralisation The presence of a target mineral in a mass of host rock.
NAV Net asset value.
NPV Net present value.
Opencast/Open pit Surface mining in which the ore is extracted from a pit. The geometry of the pit may vary with the characteristics of the ore body.
OPEX Operating expenditure.
Orebody A continuous well-defined mass of material of sufficient ore content to make extraction economically
feasible.
Overburden The alluvium and rock that must be removed in order to expose an ore deposit.
Parcel A collection of diamonds of various sizes made available for sale as a single package.
Payability Economic viability of a mineral deposit.
Percussion drilling A drilling method where the rock is broken by a rotary bit into chips that are blown up the hole to be sampled.
Primary deposit With reference to the deposition of diamonds, these deposits include kimberlite pipes, dykes, blows and fissures as well as lamproites. Contrasted with alluvial.
Primary Gravel Potentially diamondiferous alluvial gravels occurring on the Hospitaal and Uitdraai properties.
Probable reserves The economically mineable material derived from a Measured and/or Indicated Diamond Resource. It is estimated with a lower level of confidence than a Proved Reserve. It is inclusive of diluting materials and allows for losses that may occur when the material is mined.Appropriate assessments, which may include feasibility studies, have been carried out, including consideration of, and modification by, realistically assumed mining, metallurgical, economic, marketing, legal, environmental, social and governmental factors. These assessments demonstrate at the time of reporting that extraction is reasonably justified.
Proven reserves The economically mineable material derived from a Measured Diamond Resource. It is estimated with a high level of confidence. It is inclusive of diluting materials and allows for losses that may occur when the material is mined. Appropriate assessments, which may include feasibility studies, have been carried out, including consideration of, and modification by, realistically assumed mining, metallurgical, economic,
marketing, legal, environmental, social and governmental factors. These assessments demonstrate at the time of reporting that extraction is reasonably justified.
Rehabilitation The process of restoring mined land to a condition approximating to a greater or lesser degree its
original state. Reclamation standards are determined by the South African Department of Minerals and
Energy Affairs and address ground and surface water, topsoil, final slope gradients, waste handling and revegetation issues.
Rooikoppie Gravel A thin deflationary (wind eroded) gravel surface on old terraces. The cobbles are usually weathered reddish brown. The volume of this gravel has been reduced by wind erosion and it usually has a higher diamond grade.
Sample The removal of a small amount of rock pertaining to the deposit, which is used to estimate the grade of the deposit and other geological parameters. Kimberlite samples for the recovery of diamonds are usually several hundred tonnes per sample.
Sampling Taking small pieces of rock at intervals along exposed mineralisation for assay (to determine the mineral content). Bulk samples in the case of kimberlites.
Sandstone A fine to very coarse grained arenaceous sedimentary rock consisting of silicate group minerals,
e.g. sand.
Sedimentary Formed by the deposition of solid fragmental or chemical material that originates from weathering of rocks and is transported from a source to a site of deposition.
Shale A fine grained argillaceous sedimentary rock consisting of clays.
Slimes The fine fraction of tailings discharged from a processing plant without being treated; in the case of
diamonds, usually that fraction which is less than 1 mm in size.
Slimes dam A storage facility for all fine waste products from the processing plant.
Specific gravity Measure of quantity of mass per unit of volume, density.
Stockpile A store of unprocessed ore or marginal grade material.
Stone size Average size of the diamonds, expressed as carats/stone.
Stones Diamonds.
Stripping Removal of waste overburden covering the mineral deposit.
Stripping ratio Ratio of ore rock to waste rock.
Tailings The waste products of the processing circuit. These may still contain very small quantities of the
economic mineral.
Tailings dam Dams or dumps created from waste material from processed ore after the economically recoverable metal or mineral has been extracted.
Tonnage Quantities where the tonne is an appropriate unit of measure.Typically used to measure reserves of metalbearing material in situ or quantities of ore and waste material mined, transported or milled.
Trenching Making elongated open-air excavations for the purposes of mapping and sampling.
Volcanic Igneous rocks that have reached or nearly reached the earth’s surface before solidifying, for example lavas.
Waste rock Rock with an insufficient diamond content to justify processing.
Weathered rock Rock which has been broken down by the influences of water and air and which becomes softened and partially decomposed.
Xenoliths An inclusion of a pre-existing rock into an igneous rock.
Yield/Recovered grade The actual grade of ore realised after the mining and treatment process.
| Units | Description |
| ° | Degree |
| °C | Degrees Celsius |
| Cm | Centimetre |
| cpht | Carat per hundred tonnes |
| ct | Carat |
| ct/ht | Carat per hundred tonnes |
| ha | Hectare |
| km | Kilometre |
| km2 | Square kilometres |
| m | Metre |
| m | Million |
| m2 | Square metres |
| m3 | Cubic metre |
| ppm | Parts per million |
| R/t | South African Rands per tonne |
| t | Tonne |
| tpa | Tonnes per annum |
| tph | Tonnes per hour |
| tpm | Tonnes per month |
| US$/ct | United States Dollar per carat |
