Conversion factors and resource category definitions:
| Units |
|
Equivalents |
|
Hectare
|
=
|
2.471 acres
|
|
Metre
|
=
|
3.281 feet
|
|
Kilometre
|
=
|
0.621 miles
|
|
Gram
|
=
|
0.032 troy ounces
|
|
Tonne
|
=
|
1.102 short tons (2,000 lbs)
|
|
Gram/tonne
|
=
|
0.029 troy ounces/ton
|
|
Mile
|
=
|
5,280 feet
|
|
Tonne
|
=
|
2,204.6 lb
|
|
Short ton
|
=
|
2,000 lb
|
Resource category (classification) definitions-
The discussion of mineral deposit classifications in this AIF adheres to the resource/reserve definitions and classification criteria developed by the Canadian Institute of Mining and Metallurgy in 2005.
Estimated mineral resources fall into two broad categories, dependent on whether their economic viability has been established, namely: “resources” (economic viability not established) and ore “reserves” (viable economic production is feasible).
Resources are sub-divided into categories depending on the confidence level of the estimate based on level of detail of sampling and geological understanding of the deposit.
The categories, from lowest confidence to highest confidence, are inferred resource, indicated resource and measured resource. Reserves are similarly sub-divided by order of confidence into probable (lowest) and proven (highest). These classifications can be more particularly described as follows:
A “mineral resource” is a concentration or occurrence of diamonds, natural solid inorganic material, or natural solid fossilised organic material, including base and precious metals, coal, and industrial minerals 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.
An “inferred mineral resource” is that part of a mineral resource for which quantity and grade or quality can be estimated on the basis of geological evidence and limited sampling and geological and grade continuity reasonably assumed, but not verified. The estimate is based on limited information and sampling, gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes.
An “indicated mineral resource” is that part of a mineral resource for which quantity, grade or quality, densities, shape and physical characteristics can be estimated with a level of confidence sufficient to allow the appropriate application of technical and economic parameters, to support mine planning and evaluation of the economic viability of the deposit.
The estimate is based on detailed and reliable exploration and testing information, gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that are spaced sufficiently closely for geological and grade continuity to be reasonably assumed.
A “measured mineral resource” is that part of a mineral resource for which quantity, grade or quality, densities, shape and physical characteristics are so well established that they can be estimated with a high degree of accuracy. The estimate 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 that are spaced sufficiently closely to confirm both geological and grade continuity.
A “mineral reserve” is the economically mineable part of a measured or indicated mineral resource, demonstrated by at least a Preliminary Feasibility Study.v 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.
A “probable mineral reserve” is the economically mineable part of an indicated and, in some circumstances, a measured 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. The US Securities and Exchange Commission require permits in hand or imminent to classify mineralized material as reserves.
A “proven mineral reserve” is the economically mineable part of a measured 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 is justified. The US Securities and Exchange Commission requires permits to be in-hand or imminent to classify mineralized material as (ore) reserves.
A
Alloy: A compound consisting of two or more metals.
Alluvium: A deposit of sedimentary material in river beds, lakes, flood plains or at the base of mountain slopes.
Assay: A chemical test performed on a sample of ores or minerals to determine the amount of valuable metals contained therein.
Archean (pronounced /ɑr’ki:ən/, also spelled Archaean): Formerly called Archaeozoic (/ɑrkiə’zoʊɪk/), also spelled Archeozoic or Archæozoic, is a geologic eon before the Paleoproterozoic Era of the Proterozoic Eon, before 2.5 billion years ago.
Au Eq: Gold Equivalent Ounces - The combined grade of gold and silver metals expressed as a gold equivalent at Great Basin Gold. (It can also include other metals).
B
Backfill: Waste material used to fill the void created by mining activities.
Ball Mill: A steel cylinder filled with steel balls into which crushed ore is fed. The ball mill is rotated, causing the balls to cascade and grind the ore.
BEE: Black Economic Empowerment, a reference to South African legislative initiatives designed to help redress past injustices to historically disadvantaged persons.
BLM: Bureau of Land Management
C
Carlin Type Deposit: Very fine grain gold. The Carlin Trend, where Hollister is located, is situated in northeastern Nevada and consists of a 60km northwest/southeast line of major gold deposits.
Chert: A type of rock that includes flint and agate. It sometimes has fossils in it, usually shells. It is a sedimentary rock, and it is very hard. It is made from quartz. The color of chertz is usually white or gray, but can be red, yellow or dark grey. If there is a lot of iron oxide in the chert it can be dark red; this type of chert is called "jasper."
CIL: Carbon-in-leach process which integrates leaching and carbon-in-pulp into a single unit process operation.
CICA: Canadian Institute of Chartered Accountants.
cmg/t: Centimetre grams per tonne
Concentrate: A fine, powdery product of the milling process containing a high percentage of valuable metal.
CSA: Canadian Securities Administrators
CSI: Corporate Social Investment
CSR: Corporate Social Responsibility
Cut-off Grade: The grade below which mineralization is not included in the assessment of ore resources/reserves.
D
Deposit: A body of rock containing a concentration of minerals.
Detritus: A geological term used to describe particles of rock derived from pre-existing rock through processes of weathering and erosion. Detrital particles can consist of lithic fragments (particles of recognizable rock), or of monomineralic fragments (mineral grains). These particles are often transported through sedimentary processes into depositional systems such as riverbeds, lakes or the ocean forming sedimentary successions.
Development: Underground work carried out for the purpose of opening up a mineral deposit. Includes shaft sinking, crosscutting, drifting and raising.
Dip: The angle at which a vein, structure or rock bed is inclined from the horizontal as measured at right angles to the strike.
DMR: The Department of Mineral Resources (Previously the Department of Minerals and Energy) for South Africa.
Drift: A horizontal underground development that follows along the length of a rock formation as opposed to a crosscut, which crosses the rock formation.
E
EA: Environmental Assessment
Environmental Impact Study (EIS): A written report, compiled prior to a production decision that examines the effects proposed mining activities will have on the natural surroundings and environment.
Epithermal Deposit: A type of deposit formed at low temperature (50-200°C), usually within one kilometre of the earth’s surface, often as structurally controlled veins.
Exploration: Prospecting, sampling, mapping, diamond drilling and other work involved in searching for ore.
F
Feasibility Study: An economic study assessing whether a mineral deposit can be mined profitably.
G
GAAP: Generally Accepted Accounting Practices
g/t: Grams per ton
Geophysical survey: A scientific method of prospecting that measures the physical properties of rock formations. Common properties investigated include magnetism, specific gravity, electrical conductivity and radioactivity.
H
Ha: Hectares
HDB: Hollister Development Block, a portion of the Hollister Property in Nevada.
HDSA: Historically Disadvantaged South African, a category of person intended to benefit from BEE laws.
High-grade: A rich ore with high metal content.
I
I-Drift: An access tunnel which follows along the vein.
Indicated Mineral Resource: The portion of a mineral resource for which quantity, grade or quality, densities, shape and physical characteristics can be estimated with a level of confidence sufficient to allow the appropriate application of technical and economic parameters, to support mine planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration and testing information, gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that are spaced sufficiently closely for geological and grade continuity to be reasonably assumed.
Induced Polarization (IP): A geophysical survey method developed for ore exploration purposes.
Inferred Mineral Resource: The portion of a mineral resource for which quantity and grade or quality can be estimated on the basis of geological evidence and limited sampling and geological and grade continuity reasonably assumed, but not verified. The estimate is based on limited information and sampling, gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes.
IRR: Internal Rate of Return – the discount rate that would have to be applied to the projected future cash flows from an asset to make the Net Present Value of the asset worth zero.
J
JIBAR: Johannesburg inter-banking borrowing rate
JSE: Johannesburg Securities Exchange Limited, one of the three stock exchanges on which our common shares are listed.
K
L
LHS: Long-hole stoping
Lode: A mineral deposit contained within solid rock.
LOM: Life-of-Mine, the period of time that a mine is operational and extracting ore, prior to initiating closure and reclamation activities.
M
Measured Mineral Resource: The portion of a mineral resource for which quantity, grade or quality, densities, shape and physical characteristics are so well established that they can be estimated with a high level of accuracy. The estimate 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 that are spaced sufficiently closely to confirm both geological and grade continuity.
MEGA: Mpumalanga Economic Growth Agency
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.
Mineral Resource: A concentration or occurrence of diamonds, natural solid inorganic material, or natural solid fossilised organic material, including base and precious metals, coal, and industrial minerals 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 Symbols:
Au – Gold
Ag – Silver
As – Arsenic
Cu – Copper
Hg – Mercury
Mo – Molybdenum
Pb – Lead
Sb – Antimony
Se – Selenium
Zn – Zinc
MPRDA: Mineral and Petroleum Resources Development Act, 2002 (RSA)
N
NDEP: Nevada Division of Environmental Protection
NI 43-101: National Instrument 43-101 – the national securities law instrument in Canada, regarding standards of disclosure for mineral projects.
NPV - Net Present Value: The current value of the discounted projected future cash flows from an asset at an assumed % discount rate and a form of proxy value for the asset. It is defined as the total present value (PV) of a time series of cash flows. It is a standard method for using the time value of money to appraise long-term projects. Used for capital budgeting, and widely throughout economics, it measures the excess or shortfall of cash flows, in present value terms, once financing charges are met.
NYSE Amex: New York based Stock Exchange (formerly the American Stock Exchange – Amex and NYSE Alternext) and one of the three stock exchanges on which Great Basin Gold’s common shares are listed.
O
Orebody: A natural concentration of valuable material that can be extracted and sold at a profit.
Oreshoot: The portion, or length, of a vein or other structure that carries sufficient valuable minerals to be extracted profitably.
Oz/ton: troy ounces per ton
P
Paleoplacer or Witwatersrand Gold Deposit: An ancient surficial deposit that was formed by mechanical concentration of heavy mineral particles, such as gold, from weathered debris which has since been covered by younger rocks and is no longer visible on surface. The Witwatersrand Basin in South Africa hosts the most well known examples of this type of gold deposit.
Probable Mineral Reserve: The economically mineable part of an Indicated and, in some circumstances, a measured 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. The US Securities and Exchange Commission require permits in hand or imminent to classify mineralized material as reserves.
Proven Mineral Reserve: The economically mineable part of a measured 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 is justified. The US Securities and Exchange Commission requires permits to be in-hand or imminent to classify mineralized material as (ore) reserves.
Put Option: An option which gives the holder the right but not the obligation to sell shares (or other financial instruments) at a fixed price on or before a given date.
Q
Recovery: The percentage of valuable metal in ore that is recovered by metallurgical treatment.
RIB: Rapid Infiltration Basin
RSA: Republic of South Africa
R
Recovery: The percentage of valuable metal in ore that is recovered by metallurgical treatment.
RIB: Rapid Infiltration Basin
RSA: Republic of South Africa
S
SAG Mill: A semi-autogenous mill that grinds rock into fine powder, within which the grinding media consists of larger chunks of rocks and steel balls.
SAICA: South African Institute of Chartered Accountants
SEC: United States Securities and Exchange Commission
Shaft: A vertical or inclined excavation in rock that provides access to an orebody. They are generally equipped with a hoist at the top to lower and raise a conveyance for handling workers and/or materials.
Stope: An excavation in a mine from which ore is, or was, extracted.
Strike length: The distance and direction along which drilling results have established mineralization.
Sulphide: A compound of sulphur with another element, typically a metallic element or compound.
T
Tailings: Material rejected from a mill after most of the recoverable valuable minerals have been extracted.
Ton (imperial): 2,000 lb
Tonne or “t” (metric): 2,204.6 lb
Trend: The direction, in the horizontal plane, of a linear geological feature such as an ore zone, measured from true north.
TSX: Toronto Stock Exchange, one of the three stock exchanges on which Great Basin Gold’s common shares are listed.
U
Unconformity: A buried erosion surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous.
V
Vein: A fissure, fault or crack in a rock filled by minerals that have travelled upwards from some deep source.
VWAP: Volume-Weighted Average Price
W
WIS: Waste Information System.
X
Y
Z
ZAR or R: South Africa’s national currency, the Rand.
Zone: An area of distinct mineralization.
