| Fri 23 Jan 2009, 12:18 | | LAF - Lonrho - Lonrho Mining Update |
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LAF
LOLAF
LAF - Lonrho - Lonrho Mining Update
Lonrho Plc
(Formerly Lonrho Africa Plc)
(Incorporated and registered in England and Wales)
(Registration number 2805337)
(Share code: LAF; ISIN number: GB0002568813)
("Lonrho" or "the Company")
Lonrho Mining Update
23 January 2009
Lonrho (AIM: LONR), the conglomerate with a structured portfolio of African
investments, is pleased to note that Lonrho Mining Ltd (formerly known as
Nare Diamonds), which is owned 24.16% by Lonrho, has reported a kimberlite
discovery and upgraded the potential of the Lulo Diamond project.
Set out below is the text of the announcement released by Lonrho Mining to
the Australian Securities Exchange earlier today:
HIGHLIGHTS
- Significant results from field-based exploration at Lulo Diamond
Concession, Angola.
- High counts of kimberlitic indicator minerals reported from all six
aeromagnetic targets sampled in December 2008.
- K72 and adjacent K71 targets reported both pyrope-garnets and picro-
ilmenites, with K72 positively identified as a Group 1 kimberlite pipe.
- K72 discovery supported by high alluvial diamond grades of 9-20cpht
from historical bulk sampling from nearby Canguige River.
- Increases confidence that most of the 217 aeromagnetic anomalies in the
Lulo field are related to kimberlite pipes.
- Planning underway for dry season drilling and bulk sampling program at
K72 and eight other selected targets.
Australian-based diamond exploration company Lonrho Mining Limited (ASX:
LOM) is pleased to report highly encouraging results from its first major
field-based exploration program at the Lulo Diamond Concession in north-
eastern Angola.
Field-based inspection and surface sampling of the first six of a total of
217 targets derived from a high-resolution aeromagnetic/radiometric survey
completed last year has returned very high levels of kimberlitic indicator
minerals, with one of the anomalies, K72, positively identified by Lonhro`s
exploration team as a Group 1 kimberlite pipe.
The high counts of indicator minerals pyrope-garnets and picro-ilmenite,
combined with the presence of indicator-rich kimberlite outcrop, has
substantially upgraded the potential of the Lulo Concession to host multiple
diamond-bearing kimberlite pipes. A total of 217 magnetic anomalies have
been identified in the field, possibly related to kimberlite pipes.
The new results have been reviewed by Lonhro`s Consulting Geologist, Manfred
Marx, and independently reviewed by highly experienced Consulting
Geophysicist, E.O. Kostlin, and experienced Australian-based diamond
geologist, David Jones.
They are considered to be comparable to some of the best early-stage
exploration results seen in the diamond industry, including those achieved
in the early stages of the world-class Oropa Diamond Mine in Botswana - a
discovery with which Mr Marx was closely involved.
The Lulo Concession covers an area of 3,000km2 on the eastern margin of the
Cuango River catchment area, 650km east of Luanda in the Lunda Norte
Province of north-eastern Angola.
Lonhro has signed Joint Venture agreements with Endiama, the national
diamond company of Angola and exclusive concessionary for the Angolan
diamond mining rights, to develop this highly prospective Concession. The
Company will have an initial 39% interest in all kimberlite deposits
discovered on the Concession, decreasing to 30% after recoupment of its
investment, and a 40% interest in all alluvial deposits discovered on the
tenements.
December 2008 Field Exploration Program
During December, Lonhro`s exploration team completed detailed field
inspection of six priority targets derived from a helicopter-borne high
resolution MIDAS system aeromagnetic/radiometric survey completed by Fugro
Airborne Surveys in early 2008.
This survey covered an area of 1,000km2 over the diamond bearing Cacuilo and
Lulo River catchments. The north-south flight lines were flown at an
altitude of 25 metres above the surface and at 100m line spacing. The
resulting data is of exceptionally high quality.
The interpretation of this data was completed by Consulting Geophysicist
E.O. Kostlin, who was employed for 37 years by Anglo American Corporation
and De Beers Diamond Mines and their subsidiary companies. He concluded that
the 217 dipolar magnetic anomalies identified are in all likelihood due to
kimberlites and/or kimberlite magma blows. This is supported by the 27
kimberlite pipes reported within the Lulo concession area during colonial
times.
The objective of the field program was to map the surface geology of the
kimberlite targets and to collect a 20kg to 40kg surface loam sample from
each. The presence of kimberlitic indicator minerals within these soil
samples would point to an underlying kimberlite pipe; secondly, the
geochemistry of the grains is generally a reflection of the diamond grade of
the host rock.
Heavy Mineral Results
At the six locations, a single -2 mm screened soil sample was collected,
weighing 20kg to 40kg, at the central point of the anomaly. The material was
then concentrated using a gold pan, dried, packaged and delivered to the MSA
Group laboratories in Johannesburg, South Africa.
Significantly, all six of these locations produced significant counts of
kimberlitic indicator minerals; as such, they are considered to have a high
probability of being related to underlying kimberlite pipes.
In addition, a pyrope-garnet/picro-ilmenite rich kimberlite outcrop was
identified on the summit of hill at the K72 target, which has a surface area
of about 30 hectares (see Figures 1 and 2 below). The K72
aeromagnetic/satellite/topgraphic feature was identified from field-based
inspection as a Group 1 kimberlite pipe.
The sample processing at the MSA Group laboratories included screening into
3 size fractions (1.0mm, 0.5mm and 0.3mm) which were weighed and
concentrated using TBE heavy liquid.
Where necessary, the concentrates were re-concentrated using magnetic
separation. These concentrates were then sorted by experienced observers.
Based on the final sorting results, a selected population of kimberlitic
indicator mineral grains will be microprobed. The geochemical analyses have
a bearing on the diamond content of the host kimberlite.
This allows for the early targeting of the highest priority diamond
potential kimberlite pipes for drilling and bulk sampling.
Results are reported in Table 1 below.
TABLE 1
HEAVY MINERAL RESULTS
Anomaly Pyrope Garnets Picro Ilmenite
K6 0 204
K14 0 10
K50 0 79
K71 21 79
K72 113 126
L6 0 97
Note: Possible spinels were also reported from samples K6 and
K14.
Possible chrome iopsides were reported in sample K50.
SIGNIFICANCE OF RESULTS
Confirmation of the K72 magnetic anomaly as a Group 1 kimberlite pipe,
together with the high count of kimberlitic indicator minerals from five
other magnetic anomalies, represents a very significant step forward for the
Company. The results suggest that a very high percentage of the 217 magnetic
anomalies identified at Lulo are probably related to kimberlite pipes.
The anomalies K71 and the adjacent K72 reported pyrope garnets in addition
to the picro-ilmenite grains (see Figures 1 and 2). The fact that the
kimberlite pipes in this province appear to have distinctive indicator
mineral suites could assist in the early identification of the most
prospective diamond-bearing pipes.
For example, G10 garnets are often diagnostic of diamondiferous kimberlites.
The results of the microprobe analyses of the K72 and K71 pyrope garnets
will therefore be eagerly awaited by the Company in early February.
The significance of the K72 kimberlite discovery is enhanced by the alluvial
diamond grades of between 9 and 20cpht (carats per hundred tonnes) that were
reported during the colonial times in bulk samples taken from the Canguige
River which drains this pipe as well as other suspected neighbouring pipes
(see Figure 1).
To put this in perspective, the average grade of alluvial diamond deposits
for southern Africa is typically much lower - around 1cpht.
FORWARD PROGRAM
In light of these encouraging results, Lonhro is developing a comprehensive
three-phase forward work program to fast-track exploration of the Lulo
Concession.
Phase 1
- Confirm the existence of kimberlite pipes associated with the heavy
mineral at K50, L6, K6, K71 and K14 through a 2,500-3,000m RC drilling
program.
- Investigate the nature of anomalies K29, K30 and K212 which were not
sampled in December 2008.
- Pattern drill confirmed kimberlite pipes to confirm their dimensions.
- Conduct a limited bulk sampling program of between 800-1,000 tonnes at
the highest priority kimberlite pipes.
Phase 2
- Conduct mapping and soil sampling of a selected 50-100 magnetic
anomalies including construction of access tracks.
Phase 3
- Commence evaluation of additional magnetic/satellite image anomalies
identified in Phase 2.
Commenting on the results, Lonrho Mining`s CEO and Director, Miles Kennedy,
said the Company was excited by the results which substantially enhanced the
exploration potential of the Lulo Diamond Field.
"While clearly early stage, these results - which have been reviewed by some
of the most experienced diamond exploration geologists in the world - bear
all the hallmarks of first pass exploration within a substantial diamond
field with genuine potential to host multiple kimberlite pipes."
"We intend to fast-track exploration activities in order to test the K72
pipe and several other priority target areas with a view to confirming the
diamond potential of these structures as quickly as possible."
LONRHO ENQUIRIES
Lonrho Plc +44 (0)20 7016 5105
David Lenigas, Executive Chairman +44 (0)7881 825 378
Geoffrey White, Chief Executive +44 (0)7717 307 308
Officer
Emma de Borchgrave, Executive +44 (0)7867 785 177
Director
Pelham PR
Charles Vivian +44 (0) 20 7743 6672
+44 (0) 7977 297903
James MacFarlane +44 (0) 20 7743 6375
+44 (0) 7841 672831
South African sponsor to Lonrho Plc
Java Capital (Proprietary) Limited
Date: 23/01/2009 12:18:01 Produced by the JSE SENS Department.
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