A
Aeromagnetic
refers to a geophysical magnetic survey carried out above the ground commonly using a helicopter or a fixed wing aircraft
Alluvial
deposits of diamonds which have been removed from the primary source by natural erosive action over millions of years, and eventually deposited in a new environment such as a river bed, an ocean floor or a shoreline
Autogenous mill
so-called due to the self-grinding of the ore: a rotating drum throws larger rocks of ore in a cascading motion which causes impact breakage of larger rocks and compressive grinding of finer particles
B
BEE
black economic empowerment
Bulk sample
a large sample for the purpose of estimating the grade of a diamond deposit and to produce a large enough quantity of diamonds to enable an evaluation of diamond quality
brecciated volcaniclastic Kimberlite
resedimented volcaniclastic kimberlite with 40% to 75% granite clasts
C
Carat or ct
a measure of weight used for diamonds, equivalent to 0.2 grams
Cpht
carats per hundred tonnes
Craton
a part of the Earth’s crust which has been relatively stable for a very long period
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
ctpa
carats per annum
D
Dense Media Separation or DMS
a gravity separation process using a solid/liquid suspension
Diamond grade
the content of diamonds, measured in carats, within a volume or mass of rock
Diamondiferous
containing diamonds
Drawpoint
openings on the sides of the drift going up into the block cave
E
EBITDA
earnings before interest, tax, depreciation and amortisation
Eluvial
a mass of sand, silt, etc: a product of the erosion of rocks that has remained in its place of origin; derived by in-situ weathering only, or in-situ weathering with gravitational movement
EPS
earnings per share
Exploration
prospecting, sampling, mapping, diamond drilling and other work involved in the search for mineralisation
F
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
Fissure
informal term for a narrow, vertical, vein-like kimberlite dyke
FY
Full Year
G
Geophysical prospecting
the prospecting of an area in which physical properties (e.g. resistivity, gravity, conductivity, magnetic properties) unique to the rocks in the area are quantitatively measured by one or more geophysical methods
Geophysics
mineral exploration techniques which measure the changes in various physical properties of the Earth’s crust
– and which may be ground-based or airborne; measures electrical, magnetic, gravity or other properties
Gravity – a technique which measures variations in the local gravity field
Magnetic – an airborne or ground-based technique which measures variations in the Earth’s magnetic field
Electromagnetic – any of a large number of geophysical techniques which measure the electrical properties of the Earth and are very applicable to mineral exploration
Grade
the content of diamonds, measured in carats, within a volume or mass of rock
Granite
a medium to coarse-grained felsic intrusive rock that contains 10-50 per cent. quartz
Grizzly
iron bars (over an ore pass or a hopper) spaced to control the size of broken rock going into the ore pass, or crushing plant
Group I kimberlite
Group I kimberlites contain ilmenite as an accessory mineral and have an approximate age of 80 million years. Koffiefontein and Cullinan are examples of Group I kimberlites.
Group II kimberlite
otherwise known as orangeites or micaceous kimberlites, Group II kimberlites do not contain ilmenite as an accessory mineral. The absence of ilmenite indicates that a Group II kimberlite has different sources of magma and perhaps intrusion history to Group I and it is thought to have been formed by contamination of kimberlitic magma during its passage through the Earth’s crust. Group II kimberlites have an approximate age of 120 million years old. The Fissure mines and Finsch are examples of Group II kimberlites.
H
H1 or H2
first half, or second half, of the financial year
ha
hectare, equal to 10,000 square metres
Hardrock
with reference to the deposition of diamonds, these deposits include kimberlite pipes, dykes, blows and fissures as well as lamproites
I
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)
Indicator minerals
minerals that can help locate the presence and establish the diamond-bearing potential of kimberlite; these minerals do not weather easily and are preserved in soils and gravels
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)
In situ
in its original place; most often used to refer to the location of the mineral resources
J
Jig Plant
small plant that concentrates diamonds and other relatively dense minerals
K
Karoo time
approximately 300 Ma to 80 Ma ago
Kimberlite
a brecciated ultrabasic igneous rock containing phlogopite mica, bronzite pyroxene and ilmenite; kimberlites may or may not contain diamonds
kimberlite indicator minerals
diamonds, garnets, and several other minerals, the presence of which are used to identify kimberlitic rocks
ktpa
thousand tonnes per annum
M
Ma
one million years
Massive
a rock texture that has no layering or regular structure
Mctpa
million carats per annum
Mcts
million carats
Measured 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 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.
Milling plant
crushing plant; milling implies finer grinding
Mini bulk-sample
a large sample, commonly in the order of 50 tonnes to 100 tonnes, for the purpose of determining the exploration potential of a diamond prospect
Mt
million tonnes
Mtpa
million tonnes per annum
O
Opencast or open pit
mining in which ore that occurs close to the Earth’s surface is extracted from a pit or quarry
Optical sort plant
a plant designed to capture diamonds that don’t fluoresce well under X-ray (i.e. Type II diamonds)
Orebody
a continuous well-defined mass of material of sufficient ore content to make extraction feasible
Overburden
material of little or no value, which overlies rock formations of economic interest
P
pa
per annum
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 derived from primary deposits
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 proven 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
R
Rehabilitation
the process of restoring mined land to a condition approximating to a greater or lesser degree its original state
Reverse circulation
a method of percussion drilling used to provide large samples of the subsurface rocks
ROM
run-of-mine
S
Shaft
an underground vertical or inclined passageway
Sink
high density material in which diamonds are concentrated
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 1mm in size
Slimes dam
a storage facility for all fine waste products from the processing plant
Slurry
a thick suspension of solids in a liquid
Slusher drift block cave
a block cave where drawpoints are not loaded individually, but are allowed to empty into a drift that is cleaned by a slusher (or a scraper winch)
Stockpile
a store of unprocessed ore
Strike
the strike line of a bed, fault, or other planar feature is a line representing the intersection of that feature with a horizontal plane
T
t
metric tonne
Tailings
material left over after processing ore
Tailings dump
dumps created of 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 target commodity bearing material or quantities of ore and waste material mined, transported or milled
tpa
tonnes per annum
tpd
tonnes per day
tph
tonnes per hour
tpm
tonnes per month
Transvaal Supergroup
a sequence of sedimentary rocks in Southern Africa deposited between 2.65 and 2.05 Ga
Type II diamonds
Type II diamonds are defined by containing no detectable nitrogen and are often colourless or brown
V
Volcaniclastic
describes a sedimentary rock composed of fragments of volcanic rocks
X
X-ray
a form of electromagnetic radiation
Y
Yield / Recovered grade
the actual grade of ore realised after the mining and treatment process