Glossary

 
Basalt
Dark colored, fine-grained volcanic igneous rock.
Block cave
An underground mining method in which large blocks of ore are undercut causing the ore to break and fall under gravity creating a cave.
Blow
A thickening (usually more than 10m thick) of a dyke.
Breccia
Rock composed of sharp-angled foreign fragments embedded in a fine-grained matrix.
Boxcut
The surface opening of an underground mine decline.
Bulk sample
A large sample of mineralised rock, frequently hundreds of tonnes, selected in such a manner as to be representative of the potential orebody being sampled.
Calcite
The mineral calcium carbonate.
Carat or ct
A unit of weight for diamonds, equivalent to 0.2 of a gram.
Country rock
The rock bodies which enclose an intrusive mass of igneous rock.
cpht
carats per hundred tonnes.
Diopside
A crystallized variety of pyroxene, of a clear, grayish green colour.
Diamond drilling
A method of exploration drilling which uses a drill bit embedded with industrial diamonds to cut out a core of rock.
Drawpoint
An underground opening at the bottom of a slope through which broken ore is extracted.
Dyke
A sheet-like body of igneous rock which is discordant i.e. cuts across the bedding or structural planes of the host rock.
Facies
Distinctive rock sub-type.
Feasibility study
A comprehensive study, including final engineering, undertaken to determine the economic viability of a project; the conclusion will determine if a production decision can be made and is used for financing arrangements. Typically, the accuracy of these studies is in the 10 per cent range.
Geophysical survey
The exploration of an area in which physical properties relating to geology are used. Geophysical methods include seismic, magnetic, electromagnetic, gravity and induced polarization techniques.
Grade
The relative mass of diamonds in a mass of rock.
Hypabyssal
A magmatic intrusion which has solidified before reaching the earth’s surface.
Kimberlite
An uneven grained, ultramafic, intrusive rock in which the visible minerals may include olivine, phlogopite, pyrope garnet, picroilmenite and chrome-diopside cemented by a groundmass, which may include serpentine, calcite and chromate. Kimberlite may be diamondiferous and, along with olivine lamproites, are the only know primary source of diamonds.
Indicated mineral resource
That part of a mineral resource for which tonnage, densities, shape, physical characteristics, grade and mineral content 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.
Inferred mineral resource
That part of a mineral resource for which tonnage, grade and mineral content can be estimated with a low level of confidence. It is inferred from geological evidence and assumed but not verified geological and/or grade continuity. It is based on information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes which may be of limited or uncertain quality and reliability.
In-situ
Rock occurring as was originally emplaced with all associated after emplacement episodes that have tectonically and structurally influenced the rock as seen today.
Measured mineral resource
That part of a mineral resource for which tonnage, densities, shape,physical characteristics, grade and mineral content 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.
Macrodiamonds
Diamonds that are greater than 0.5mm in the longest axial dimension.
Microdiamond
Diamonds that are less than 0.5mm in all axial dimensions.
Mtpa
million tonnes per annum
Olivine
An olive-green, silicate mineral rich in magnesium and iron. It is a common rock-forming mineral in the lower part of the crust and the upper mantle.
Pipe or diatreme
The carrot shaped volcanic vent that has formed by explosive action and is characteristic of kimberlite eruptions. Diatremes typically cut through non-volcanic basement rocks.
Phlogopite
A brown form of mica consisting of hydrous silicate of potassium and magnesium and aluminum.
Prefeasibility study
Preliminary feasibility (prefeasibility) studies are the intermediate step in project evaluation. At this stage there is sufficient drilling, bulk sampling and process test work for preliminary engineering. Typically, the accuracy of these studies is in the 15-25 per cent range. The goal of these studies is to determine the mining and milling extraction methods and rates, the product recoveries, environmental and permitting issues, preliminary capital and operating cost estimates.
RoM or Run-of-mine
Tonnage of rock as it comes out of a mine before crushing or any other form of treatment.
Slimes dam
Sealed impoundment to collect fine grained material from the recovery plant.
Tailings
Material rejected from a mill after most of the recoverable valuable minerals have been extracted.
tph
Tonnes per hour.
Xenolith
An inclusion of a pre-existing rock in an igneous rock, often derived from the country rocks that have been intruded through.
 

The Lace Project

Map of South Africa indicating the location of the Lace project

The Lace Project is located 20km from Kroonstad in the Free State province of South Africa. The project contains an estimated 14 million carats of diamonds in tailings and kimberlite. Additional kimberlites have also been identified on the group’s adjoining properties.



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