Annual Report and Accounts 2013
Petra Diamonds Limited 137
Overview
Performance Review
Strategic Review
Sustainability
Corporate Governance
Group Accounts
Glossary
“AGM”
annual general meeting
“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
“BEE”
black economic empowerment
“Block caving”
a method of mining in which large blocks of
ore are undercut so that the ore breaks and
caves under its own weight. The undercut
zone is initially drilled and blasted and some
broken ore is drawn down to create a void
into which initial caving of the overlying ore
can take place. As more broken ore is drawn
progressively following cave initiation, the
cave propagates upwards through the
orebody or block until the overlying rock
also caves and surface subsidence occurs.
The broken ore is removed through the
production or extraction level developed
below the undercut level. Once the caves
have been propagated, it is a low cost
mining method which is capable of
automation to produce an underground
“rock factory”
“calcrete”
hardened deposits of calcium carbonate
formed in the near surface environment
in arid or semi-arid environments
“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
“Capex”
capital expenditure
“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
“ctpa”
carats per annum
“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
“deflation soil
sampling the topmost soil layer to obtain
sampling”
heavy mineral grains that have been
concentrated by wind action in arid or
semi-arid environments
“diamondiferous”
containing diamonds
“drawpoint”
an opening through which ore from a higher
level can fall and subsequently be loaded
“EBITDA”
earnings before interest, tax, depreciation
and amortisation
“EPS”
earnings per share
“fissure”
informal term for a narrow, vertical,
vein-like kimberlite dyke
“FY”
Petra’s financial year (1 July to 30 June)
“grade”
the content of diamonds, measured in
carats, within a volume or mass of rock
“H1” or “H2”
first half, or second half, of the financial year
“iNED”
independent non-executive director
“Indicated
that part of a diamond resource for which
Resource”
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
that part of a diamond resource for
Resource”
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)
“kimberlite”
a brecciated ultrabasic igneous rock
containing phlogopite mica, bronzite
pyroxene and ilmenite; kimberlites may
or may not contain diamonds
“kimberlite
minerals that can help locate the presence
indicator
and establish the diamond-bearing
minerals”
potential of kimberlite
“Kt”
thousand tonnes
“LHD”
load haul dumper
“LOM”
life of mine
“LTI”
lost time injury; a work-related injury
resulting in the employee/contractor being
unable to attend work on the day following
the injury
“LTIFR”
lost time injury frequency rate; the number
of LTIs multiplied by 200,000 and divided
by the number of hours worked
“macrodiamond”
diamonds too large to pass through
a 0.5mm screen
“Mctpa”
million carats per annum
“Mcts”
million carats
“Measured
that part of a diamond resource for
Resource”
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
1...,129,130,131,132,133,134,135,136,137,138 140,141,142