Skip to main content Skip to submmenu Blackthorn Resources - logo

Mumbwa

The Company’s Mumbwa Project is located in west-central Zambia, approximately 200km west of the Capital Lusaka.
The Mumbwa Project comprises five contiguous prospecting licences with a total area of approximately 1000km2,  including the Mumbwa licence (8589-HQ-LPL) which hosts the Company’s flagship Kitumba Copper Project.

The Mumbwa Project lies within the southern end of a fold and thrust belt known as the Lufilian Arc, which also hosts the Zambian copper belt deposits. The oldest rocks are the Kundulungu group metasediments which belong to the upper units of the Neoproterozoic Katanga Sequence. The Kundulungu metasediments are intruded in multiple phases by the Hook Granitoid Suite.

The mineralisation at Kitumba is hosted within brecciated Hook Granitiods (syenite-diorite porphyry) and pervasive iron oxide replacement of various pre-existing rocks is a common feature. Breccia formation has been facilitated by a large N-S oriented structure known as the Kitumba Fault Zone and iron induration along the fault has resulted in the formation of a prominent hill.

The Kitumba deposit is recognised as having Iron Oxide Copper Gold (IOCG) type affinities and its geological setting display similar characteristics to other IOCG deposits, including Olympic Dam. Typical characteristics include:

•     Copper-gold mineralisation accompanied by large-scale partial to pervasive iron alteration and brecciation

•     Vertically oriented, structurally controlled hematite-rich breccia zones containing pyrite and chalcopyrite

•     Mineralisation and brecciation spatially associated with major structural intersections

•     A spatial and temporal association with the multi-phase Hook Granitoid Suite, and extensive potassic alteration

The IOCG type alteration system observed at Kitumba is zoned from north to south, with deeper level magnetite dominated alteration south of Kitumba and higher level hematite dominated alteration over Kitumba itself.


Figure 1. Mumbwa Project Licences

Copper mineralisation at Kitumba comprises a simple hypogene sulphide assemblage (Chalcopyrite,bottom) that has been extensively altered, largely redistributed and enriched to form a supergene oxide assemblage (chalcocite, malachite, cuprite, chalcosiderite, chrysocolla, ± native copper, top). Deep weathering is localised along and down the Kitumba Fault Zone and facilitated by acid generation from the weathering of pyrite has resulted in a leached zone to approximately 200m followed by a supergene enriched core above the primary hypogene zone. Supergene enrichment has facilitated the deposition of very high grade copper, resulting in some exceptional drill hole intercepts over the last 3 years (Table 1).
 

Table 1. Kitumba high grade drill hole intercepts

Hole ID

From

To

Length m

Copper Grade %

S36_038

188

493

305

4.05

KITDD_027

208

451

243

5

KITDD_031

199

365

166

7.14

KITDD_028

240

414

174

5.04

KITDD_032

183

406

223

3.22

KITDD_005

206

426

220

3.02

KITDD_006

55

477

422

1.27

KITDD_030

278

462

184

2.71

S36_032

311

498

187

2.62

KITDD_033

236

346

110

4.08


Mineral Resource Update and Ore Reserve

A JORC Code (2012) compliant Mineral Resource estimate was reported in December 2013 delivering a 25% increase in contained copper over previous estimate – 34.7Mt at 2.29% copper using a 1% cut-off for a total of 795,000 contained copper tonnes1. This update includes material in the measured category at Kitumba for the first time – 10.4Mt at 2.93% copper using a 1% cut-off. Material in the Measured and Indicated categories that can be economically extracted can be included in Ore Reserves. A revised Ore Reserve estimate was reported as part of the Kitumba Optimised Prefeasibility Study (OPFS) announcement in April 20142. Kitumba contains Proved and Probable C Mineral Reserves of 31.5Mt at 2.04% Cu for a total of 641,000t contained copper (Table 3).

[1] Reported in accordance with the JORC Code (2012) – Refer to ASX announcement ‘Kitumba Mineral Resource Update’ dated 16 December 2013. A copy of the ASX announcement is available on the Company’s website at www.blackthornresources.com.au.

2 Reported in accordance with the JORC Code (2012) – Refer to ASX announcement ‘Kitumba Optimised PFS Provides Positive Project Re-rating’ dated 29 April 2014. A copy of the ASX announcement is available on the Company’s website at www.blackthornresources.com.au.

Table 2. KITUMBA MINERAL RESOURCE  ESTIMATE# ABOVE A CUT-OFF-GRADE OF 1.0% Cu

CATEGORY

TONNES

Cu

ACID SOLUBLE Cu

Co

Au

Ag

U

DENSITY

 

(Millions)      

%                

 %   

ppm       

g/t           

g/t     

 ppm           

t/m3

Supergene Domain

Measured

6.1

3.44       

1.66

205

0.04

1.3  

25

2.51

Indicated

15.2

2.07

1.00

180

0.03

0.9

26

2.60

M&I

21.3

2.46

1.19

187

0.03

1.0

26

2.57

Inferred

0.2

1.12

0.28

124

0.16

0.4

22

2.66

Hypogene Domain

Measured

4.4

2.23

0.45

247

0.04

1.0

21

2.86

Indicated

9.0

1.93

0.57

210

0.03

0.9

32

2.83

M&I

13.4

2.03

0.53

222

0.03

0.9

28

2.84

Inferred

3.9

1.39

0.23

415

0.02

0.7

31

2.81

Combined Domain

Measured

10.5

2.93

1.15

223

0.04

1.2

2.3

2.66

Indicated

24.2

2.02

0.84

191

0.03

0.9

28

2.69

M&I

34.7

2.29

0.93

201

0.03

1.0

27

2.67

Inferred

4.1

1.38

0.23

401

0.03

0.7

31

2.80

Total

38.8

2.19

0.86

222

0.03

0.9

27

2.68

#All tabulated data has been rounded to one decimal place for tonnage and to either, no, one or two decimal places for grades.


Table 3. KITUMBA ORE RESERVE ESTIMATE AS AT APRIL 2014

 ITEM

TONNES

(Mt)

GRADE

(% Cu)

METAL

(kt Cu)

Proved Ore Reserve

11.9

2.44

291

Probable Ore Reserve

19.6

1.79

350

Total Ore Reserve

31.5

2.04

641


Optimised Prefeasibility Study

The Company released details of the OPFS to the market in April 2014. The OPFS was an update of an initial prefeasibility study released to the market in September 2013 which was timed to facilitate the preparation of a mining licence application prior to the expiration of the Mumbwa exploration licence. A one year extension to the prospecting licence was subsequently granted prior to the licence expiring, allowing time for completion of the OPFS.

The OPFS, together with the Environmental Impact Statement (EIS) which was recently submitted to the Zambian Environmental Management Agency (ZEMA), will provide the necessary support for a Mining Licence Application at Kitumba. . The application is expected to be submitted in the 3rd quarter of CY2014.

The OPFS has confirmed  that Kitumba presents an economically and technically feasible project (Table 4), justifying progressing the project through a Definitive Feasibility Study (DFS) towards Final investment Decision (FID). As part of the DFS, further drilling, focused on collecting metallurgical samples, hydrological information and additional geotechnical data will be initiated. Confirmatory test work on the flow sheet proposed in the OPFS (including a pilot plant) will be carried out to provide the necessary data to support a DFS and the detailed design work.

A series of mining options and production rates were assessed and a 3Mtpa Sub-Level Cave (SLC) was chosen as the preferred option. Mine planning is based on a dual decline design and materials handling is by truck haulage. The mine design is based on 25m sub-levels and extends to a depth of approximately 450m below surface.

Copper will be recovered using a copper leaching process comprised of crushing, grinding, flotation, pressure oxidation, atmospheric acid leaching and solvent extraction / electrowinning. The flow sheet utilises commercially proven processes and produces copper cathode product for direct sale. The flow sheet also has excess plant capacity that will allow toll treatment of copper concentrate from outside operations.
 

Figure 3. Sliced 3D rendering of the Kitumba deposit looking east with drill holes, planned development and copper shells (transparent yellow => 0.3%, orange => 1%, red => 2%)
 

Figure 2. Sliced 3D rendering of the Kitumba deposit looking north with drill holes, planned development and copper shells (transparent yellow => 0.3%, orange => 1%, red => 2%)
 

Table 4. OPFS results

METRIC        

STATISTIC

ROM Tonnes (Mt)

31.6

Head Grade (% Cu)

2.03

Contained Copper (t)

641,786***

Recovered Cu Metal Kitumba (t)

589,697

Recovered Cu Metal (Imported Con) (t)

47,394

Total Cu Metal Produced (t)

637,092

Average Cu per Annum (t)

58,000

NPV @ 8% Discount Rate (US$M)

461

Post-tax real IRR (%)

21

Construction capital (US$‘000)

680,317

Total LOM capital incl. sustaining and mine rehab (US$ ‘000)

796,223

Production Mine Life (Yrs)

11

Mine Life (Total Yrs)

14

C1 Cash Cost (US$/lb Cu)*

1.57

All in Cash Cost (US$/lb Cu)**

1.89

*C1 Cash cost includes cash cost of mining, processing, treatment, refining and transport of Cu metal to market.
**All in Cash Cost is the total cash costs, including C1 plus royalties and sustaining capital cost
*** Life Of Mine production

Note, the OPFS production target and forecast financial information derived from the production target extracted from the report  entitled ‘Kitumba Optimised PFS Provides Positive Project Re-rating’ released to ASX on 29 April 2014, includes 139kt of inferred mineral resources that is not included in the Ore Reserve estimate (less than 0.5% of the production target forecast). There is a low level of geological confidence associated with the inferred mineral resource and there is no certainty that further exploration work will result in the determination of indicated mineral resources or that the production target relating to the inferred mineral resource itself will be realised.
 

Other Mumbwa Targets

The IOCG alteration system within the Mumbwa project extends over 20km of strike length and the Company has multiple high priority targets at various stages of advancement. Copper mineralisation has recently been found at the Kakozhi and Tasmania targets. These results along with information collected in a soil geochemical survey and down hole EM completed in the 2013 field season are being integrated with the Company’s historical datasets. High priority targets will be further tested along with the requisite fieldwork for the DFS (primarily metallurgical, geotechnical and sterilisation drilling) in the 2014 field season.

Figure 4. Mumbwa Project targets on satellite image

Summary
Blackthorn Resources has a clear focus on taking its flagship Kitumba Project, through to FID and further exploration on its Mumbwa Project tenements.
 

ATTRIBUTIONS

MUMBWA EXPLORATION

The information contained on the Blackthorn Resources Website which relates to Exploration Results at the Mumbwa Project in Zambia is based on information compiled by Mr Michael J Robertson, MSc, Pr.Sci.Nat., MSAIMM who is a member of The South African Institute of Mining and Metallurgy, which is a Recognised Professional Organisation (‘RPO’). Mr Robertson has 22 years’ experience in mineral exploration and is a full-time employee of the MSA Group. Mr Robertson has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which is being undertaken to qualify as a Competent Person as defined in the 2004 Edition of the ‘Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves’. Mr Robertson consents to the inclusion on the Blackthorn Resources Website of the matters based on his information in the form and context in which it appears.

KITUMBA PROJECT

The information contained on the Blackthorn Resources Website which relates to Mineral Resources for the Kitumba Project in Zambia is extracted from the report entitled ‘Kitumba Mineral Resource Update’ released to ASX on 16 December 2013 which is available on the ASX website at www.asx.com.au or the BTR website at www.blackthornresources.com.au. The Company confirms that it is not aware of any new information or data that materially affects the information included in the original market announcement and, in the case of estimates of Mineral Resources that all material assumptions and technical parameters underpinning the estimates in the relevant market announcement continue to apply and have not materially changed. The Company confirms that the form and context in which the Competent Person’s findings are presented have not been materially modified from the original market announcement.

The information contained on the Blackthorn Resources Website which relates to Ore Reserves for the Kitumba Project in Zambia is extracted from the report entitled ‘Kitumba Optimised PFS Provides Positive Project Re-rating’ released to ASX on 29 April 2014 which is available on the ASX website at www.asx.com.au or the BTR website at www.blackthornresources.com.au. The Company confirms that it is not aware of any new information or data that materially affects the information included in the original market announcement and, in the case of estimates of Mineral Resources and Ore Reserves that all material assumptions and technical parameters underpinning the estimates in the relevant market announcement continue to apply and have not materially changed. The Company confirms that the form and context in which the Competent Person’s findings are presented have not been materially modified from the original market announcement.