Drilling Update

RNS Number : 9691G
African Mining & Exploration PLC
20 May 2011
 



AFRICAN MINING AND EXPLORATION plc

('AME' or 'the Company')

DRILLING UPDATE - KARAN LICENCE, MALI

 

African Mining & Exploration plc (AIM: AME), the AIM listed gold exploration company operating in Mali, West Africa, announces the findings of its initial Drilling Programme.

Highlights

12,269 metre Reverse Circulation ('RC') drill programme completed over four target areas within the Karan Licence;

 

Drilling targeted four prospects delineated by geochemical and geophysical data;

 

Approximately 2.9 km of the 25km structure drilled ;

 

Evidence of pervasive gold mineralisation discovered, associated with 3 of the 4 main targets;

 

Significant mineralisation found associated with quartz veining and porphyritic intrusions with dispersed low-grade halos;

 

Peak intersections include 1 metre ('m') at 11.75 grams per tonne gold ('g/t Au'), 1m at 8.62g/t Au, 1m at 5.88g/t Au, 1m at 4.73g/t Au and 2m at 3.90g/t Au.

 

Large low grade intersections include 39m at 0.21g/t and 101m at 0.11 g/t.

 

Further exploration drilling required to follow up mineralised structural targets  within the Karan Licence;

 

Screened fire assay to be completed on representative mineralised holes to detect for the presence of coarse grained gold

 

Mark Jones, Chief Executive Officer comments ''Gold mineralisation has been found on all four prospects and we are encouraged by the structures associated with the mineralisation in the host rocks indicating the presence of gold in the system. These structures are consistent with what is found elsewhere in Mali in similar terrain. Exploration remains at an early stage and the next phase aims to improve our understanding of the structures controlling mineralisation and thereby refine the next round of drilling to intersect higher grade intercepts which it is assumed are currently reflected in the larger low-grade gold halos that have been intersected''.

 

For further information, please contact:              

African Mining & Exploration plc

+44 (0)207 499 4059

Mark Jones (Chief Executive Officer)

 



Singer Capital Markets Limited

+44 (0)20 3205 7500

(Nomad and Broker)

 

James Maxwell/Jennifer Wyllie

 



Farm Street Communications

+44 (0)759 3340 107

 

+44 (0)203 176 4249

 

 

Exploration programme

The Reverse Circulation ('RC') programme completed on targets in the Karan Licence comprised a total of 83 holes for 12,269 metres drilled. To date, assays have been received for all of the holes, bringing the total number of assay results to 12,920.

Drilling was completed using a well-established international drilling contractor with rig supervision being supplied at all times by experienced AME geologists.

Sampling protocols and drilling procedures were independently assessed and approved by an independent geological consultant as part of AME's standard QA/QC review.

Drilling depths were generally planned for 175 to 200 metres to obtain coverage across the structural targets, but were constrained at some sites due to the presence of groundwater and problems with the drill rig compressor. This resulted in minor changes to the drill plan; with drill holes brought closer together to ensure lateral coverage and that near vertical structures were not missed.

 

Exploration completed since acquisition of the Licence includes the following:

12,269m RC drilling (83 drill holes);

12,920 samples collected and submitted for gold fire assay;

475 line kilometres ('km') of ground magnetic geophysics;

1.2 line km of IP - Resistivity geophysics;

875 grab and channel samples collected and analysed;

21 BLEG samples collected by Newmont under terms of an agreement;

Kouroudjin Target

A fence of 12 holes was drilled across the target focussing on regional structure defined by airborne geophysics complemented by artisanal pits.

The local geology is dominated by a fine-grained schist with moderate chlorite alteration intruded by a porphyritic unit. Silicification, quartz veining and pyrite are common throughout and appear to show more intensity proximal to the contact with the intrusion and schist. Encouragingly these areas show increased gold mineralisation, suggesting the intrusion is an important control.

Peak intersections are illustrated in Table 1 below and show the presence of both high-grade intersections generally associated with quartz veins and lower grade wider zones typically associated with disseminated sulphides and quartz stockwork alteration.

According to geophysical data and interpretation, there are a substantial number of conjugate structures present which appear to be associated with mineralisation. Further work including diamond drilling is required to achieve a better understanding of the structures and the relationship with mineralisation.

 

Table 1: Kouroudjin Target peak drill intersections

Borehole

Final Depth

(m)

Intersection

From

(m)

Intersection

To

(m)

Interval

(m)

Grade

(g/t Au)

RC11KDJ001

160

94.00

Inc.   95.00

99.00

110.0

111.0

96.00

101.0

111.0

17.00

1.00

2.00

1.00

1.03

2.63

3.9

1.08

RC11KDJ012

162

27.00

Inc.   33.00

58.00

85.00

36.00

34.00

59.00

91.00

9.00

1.00

1.00

6.00

1.17

8.62

11.75

1.04

 

Fintakourouni Target

The Fintakourouni Target is located in the north of the Karan Licence. A total of 11 RC holes were drilled of which 8 holes were drilled along a wide-spaced fence line over a strike length of approximately 500m specifically to test for the linear structure being followed by artisanal mining. Two more holes were used to test a chargeability anomaly generated by an IP-resistivity survey, whilst another hole was drilled back across RC11FIN002 to test the mineralisation intersected between 142m and 156m depth.

Drilling intersected a broad zone of meta-sediment with intermediate intrusions.  No structural interpretation has been possible and further drilling is required to establish the dip direction of the structures being followed by artisans which are not replicated at depth in drilling. 

Mineralised intersections achieved were consistent with the presence of quartz vein material and in close proximity to the intermediate shear. Further work is required to establish controls to mineralisation.

Table 2: Peak gold assays Ð Fintakourouni Target

Borehole

Final Depth

(m)

Intersection

From

(m)

Intersection

To

(m)

Interval

(m)

Grade

(g/t Au)

RC11FIN002

160

  142.0

Inc.   142.0

 148.0

156.0

144.0

149.0

14.00

2.00

1.00

0.51

1.40

2.26

RC11FIN010

162

 21.00

Inc.   24.0

27.00

27.00

6.00

3.00

1.02

1.82

 

Koukouroula Target

55 holes were drilled over Koukouroula which is an area dominated by artisanal workings. The original programme envisaged drilling toe to heel fences to provide full coverage of the prospect but this was not always possible due to the large number of active miners in the area.

The geology of Koukouroula is dominated by the dark fine grained schist, with minor porphyritic intrusions and significant quartz veining is common throughout the area, reaching up to 20 m wide intercepts and commonly associated with low-grade but anomalous gold mineralisation. The level and variety of alteration is notable and indicative of an area strongly affected by mineralising fluids.

Intersections of note for Koukouroula are illustrated below in Table 3.

 

Table 3:  Koukouroula Target Peak assay intersections.

Borehole

Final Depth (m)

Depth from

Depth to

Interval (m)

Grade (m)

RC11KOU006

146

44

45

1

2.26

RC11KOU007

150

10

11

1

4.73

RC11KOU017

162

63

70

7

1.29

RC11KOU029

189

87

99

12

0.42

RC11KOU038

150

92

113

21

0.33

and   94.00

97

3

1.2

 

The presence of a number of types of alteration and ample evidence of pyrite is encouraging and further work is required that is expected to include diamond drilling to better understand the significance of local structures in controlling mineralisation. The absence of high-grade intercepts but the presence of lower grade pervasive mineralisation remains encouraging of higher grade areas nearby.

 

Mana Target

5 holes were drilled to test the Mana target. Drilling intersected a dark fine-grained schist and highly extensive porphyritic intrusions. Intrusions are believed to be an important control in gold mineralisation in the region and the size of the intrusion intersected is encouraging. However, alteration was less in evidence and will need to be discovered at which point there is an expectation that improved grades may be discovered.

 

Table 4: Mana Target peak drill intersections

Borehole

Final Depth

(m)

Intersection

From

(m)

Intersection

To

(m)

Interval

(m)

Grade

(g/t Au)

RC11MAN001

72

68.0

69.00

1.00

0.56

RC11MAN004

156

117.0

Inc.  119.0

156.0

120.0

39.00

1.00

0.21

5.88

RC11MAN005

162

61.00

64.00

3.00

1.22

 

Coarse Grained Gold Potential


Artisanal mining at Karan has shown the presence of coarse-grained gold (+0.1 mm) on the property. Routine sample preparation for fire assay can undervalue grades where coarse-grained gold is present. Now that we have completed assays using the routine process, it is our intention to check grades in representative mineralised holes using the significantly higher-cost screened fire assay method to ensure we have not failed to capture coarse-grained gold in the results. This means that mineralised intersections may return higher grades than previously identified.

Screened fire assay takes considerably longer to complete, we therefore do not expect initial results back for approximately 6 weeks. We will update shareholders and the general market once the programme is finished.

 

Planned Exploration

The Company is currently reviewing assay results and considering the next stage of exploration. Further geophysical surveys are being planned along with some multi-element soil geochemical programmes, RAB drilling and possible diamond drilling to establish structure detail. The Company is also in consultation with Malian geological expertise familiar with the deep weathering profiles typically found in the Karan region to discuss other exploration techniques that may be beneficial. A thesis will also be undertaken this summer by a Masters student, with a focus on the alteration and mineralisation styles identified during the recent RC drilling programme. 

 

 

 

Table 5: Summary of drill data for Karan Licence exploration programme

Hole ID

Project

Intersection

Intersection

Width

Grade

Including

Depth (From - To)



From (m)

To (m)

(m)

(g/t Au)


(m)

RC11KDJ001

Kouroudjin

4

15

11

0.26

2m @ 0.66g/t

7-9m



60

62

2

0.84





94

111

17

1.03

1m @ 2.63g/t

95-96m







2m @ 3.9g/t

99-101m







1m @ 1.08g/t

110-111m

RC11KDJ002

Kouroudjin

80

98

18

0.11

1m @ 0.7ppm

80-81m

RC11KDJ003

Kouroudjin

No

Significant

Intersections




RC11KDJ004

Kouroudjin

No

Significant

Intersections




RC11KDJ005

Kouroudjin

90

97

7

0.84

1m @ 3.16g/t

90-91m

RC11KDJ006

Kouroudjin

124

127

3

0.54





156

157

1

0.59



RC11KDJ007

Kouroudjin

No

Significant

Intersections




RC11KDJ008

Kouroudjin

21

22

1

0.5





39

40

1

0.83





137

151

14

0.3

1m @ 1.98g/t

146-147m

RC11KDJ009

Kouroudjin

32

48

16

0.1





79

98

19

0.13





121

122

1

0.79



RC11KDJ010

Kouroudjin

No

Significant

Intersections




RC11KDJ011

Kouroudjin

50

70

20

0.14

1m @ 0.59g/t

57-58m

RC11KDJ012

Kouroudjin

6

7

1

0.73





9

10

1

0.55





27

36

9

1.17

1m @ 8.62g/t

33-34m



58

59

1

11.75





85

91

6

1.04

2m @ 1.93g/t

85-87m

RC11FIN001

Fintakourouni

No

Significant

Intersections




RC11FIN002

Fintakourouni

142

156

14

0.51

2m @ 1.4g/t

142-144m







1m @ 2.26g/t

148-149m

RC11FIN003

Fintakourouni

No

Significant

Intersections




RC11FIN004

Fintakourouni

No

Significant

Intersections




RC11FIN005

Fintakourouni

No

Significant

Intersections




RC11FIN006

Fintakourouni

No

Significant

Intersections




RC11FIN007

Fintakourouni

No

Significant

Intersections




RC11FIN008

Fintakourouni

No

Significant

Intersections




RC11FIN009

Fintakourouni

No

Significant

Intersections




RC11FIN010

Fintakourouni

21

27

6

1.02

3m @ 1.82g/t

24-27m

RC11FIN011

Fintakourouni

No

Significant

Intersections




RC11KOU001-3


No

Significant

Intersections




RC11KOU004

Koukouroula

72

97

25

0.1

1m @ 0.24g/t

72-73m

RC11KOU005


No

Significant

Intersections




RC11KOU006

Koukouroula

44

45

1

2.26



RC11KOU007

Koukouroula

10

11

1

4.73





123

150

27

0.07



RC11KOU008

Koukouroula

23

120

97

0.08



RC11KOU009-10


No

Significant

Intersections




RC11KOU011

Koukouroula

12

79

67

0.1



RC11KOU012


No

Significant

Intersections




RC11KOU013

Koukouroula

9

10

1

0.63



RC11KOU014

Koukouroula

105

134

29

0.1



RC11KOU015-16

Koukouroula 

No

Significant

Intersections




RC11KOU017

Koukouroula

63

70

7

1.29



RC11KOU018-28

Koukouroula 

No

Significant

Intersections




RC11KOU029

Koukouroula

64

83

19

0.1





87

99

12

0.42

5m @ 0.78g/t

89-94m

RC11KOU030-31


No

Significant

Intersections




RC11KOU032

Koukouroula

166

167

1

1.36



RC11KOU033-35


No

Significant

Intersections




RC11KOU036

Koukouroula

8

20

12

0.1



RC11KOU037

Koukouroula

154

168

14

0.1



RC11KOU038

Koukouroula

92

113

21

0.33

3m @ 1.2g/t

94-97m

RC11KOU039-43


No

Significant

Intersections




RC11KOU041

Koukouroula

95

96

1

0.94



RC11KOU044

Koukouroula

105

106

1

0.56



RC11KOU045-48


No

Significant

Intersections




RC11KOU049

Koukouroula

113

160

47

0.12

1m @ 1.80g/t

115-116m

RC11KOU050


No

Significant

Intersections




RC11KOU051

Koukouroula

5

6

1

0.83



RC11KOU052

Koukouroula

6

24

18

0.11

1m @ 0.66g/t

6-7m

RC11KOU053


No

Significant

Intersections




RC11KOU054

Koukouroula

119

120

1

0.54



RC11KOU055


No

Significant

Intersections




RC11MAN001

Mana

68

69

1

0.56



RC11MAN002

Mana

25

73

48

0.08

1m @ 0.7g/t

71-72m

RC11MAN003


No

Significant

Intersections




RC11MAN004

Mana

117

156

39

0.21

1m @ 5.88g/t

119-120

RC11MAN005

Mana

61

162

101

0.11

3m @ 1.22g/t

61-64m







1m @ 0.68g/t

150-151m

 

 

 

 

 

 

 

Figure 1. Geological map of the Karan permit, highlighting the four areas drilled

Please click on the link below to view the geological map

http://www.rns-pdf.londonstockexchange.com/rns/9691G_-2011-5-19.pdf

 

                                                                              


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