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Bushveld Minerals Ld (BMN)

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Thursday 13 December, 2012

Bushveld Minerals Ld

Mokopane Tin Project Update

RNS Number : 4129T
Bushveld Minerals Limited
13 December 2012
 



13 December 2012

For Immediate Release

Bushveld Minerals Ltd

("Bushveld" or the "Company")

Mokopane Tin Project Update

Initial Metallurgical Results from the Zaaiplaats and Groenfontein Targets

Bushveld Minerals Limited (AIM: BMN), a mineral development Company focused on iron and tin projects in southern Africa is pleased to provide an update on metallurgical testwork relating to its Mokopane Tin Project.

Bushveld's Mokopane Tin Project consists of one licence covering 13,422 ha where several targets for open-castable disseminated tin resources have been identified. The license area covers the historic Zaaiplaats and Groenfontein mines that between them formed the second largest tin mining district in South Africa, where mining ceased in the late 1980's as a result of depressed tin prices.

 

The Company recently announced an update on 4 December 2012 of its drilling programme on the second of five targets in its license area.  This drilling work is ongoing and expected to be completed within this calendar year, followed by modeling to determine the size of the resource in accordance with the JORC standard.

 

Bushveld has undertaken initial mineralogical and metallurgical testwork on bulk samples from the Groenfontein and Zaaiplaats tin targets. The objective of the testwork is to determine mineralogical characterization of the ore in terms of grain size and liberation characteristics.

 

Bulk samples from Groenfontein and Zaaiplaats targets were submitted to SGS South Africa for mineralogical characterization. The samples were crushed to 100% passing 2mm and various aliquots (representative sample of a larger sample) were extracted for mineralogical investigation. One aliquot was used for size by grade analysis involving seven different size fractions from 2000µm down to 38 µm. Another aliquot was screened into four size fractions (+1000µm, +212 µm, +75µm and -75µm) to produce transverse polished blocks of each size fraction. The blocks were then subjected to QEMSCAN analysis to determine mineral abundances, distributions per size fraction, mineral associations, liberation characteristics and grain size distributions in terms of the minerals of interest. The mineralogy results served as basis for devising preliminary process routes for the Groenfontein and Zaaiplaats ores.

 

The results are highlighted below:

·     Results from tests conducted in the well-known Zaaiplaats tin mining district are displaying similar characteristics to historical mining records, as well as significant potential for resource expansion

·     Good liberation of cassiterite through all size fractions on the Zaaiplaats ore, including significant liberation (>46%) above 1mm

·     Good liberation (>50%) of cassiterite above 212µm for the Groenfontein ore, with near-total liberation (<6% locked cassiterite) below 75µm.

·     Potential processing routes outlined for both the Groenfontein and Zaaiplaats ores.  

The next steps will entail mineral deportment characterization and densimetric profiling of the Groenfontein and Zaaiplaats ores. The results of these laboratory tests will serve to narrow down the metallurgical process route options and dictate the subsequent pilot plant test work regime to be followed. Final process design concerning the commercial plant will be based on the pilot plant test results.

Commenting on the results, Fortune Mojapelo, the Company's CEO, said "The initial metallurgical results demonstrate good liberation of the tin oxide (cassiterite) across different grinding size fractions. This is very encouraging as we seek to accelerate the development of the company's tin projects towards production in the short to medium term. The liberation characteristics shown by both Zaaiplaats and Groenfontein provide further confidence in our exploration programme which in the short term is focused on a) expanding the existing resource base by a combination of drilling on the existing targets and acquisition of additional brownfield projects in the Bushveld Complex, b) demonstrating the metallurgical treatability of the ore and c) advancing the projects towards production in the medium term."

Please refer to Appendix 1 for details on the testing methodology

 

Enquiries: [email protected]

Bushveld Minerals

Fortune Mojapelo

+27 (0) 11 268 6555

Fox Davies

Jonathan Evans

+44 (0) 20 3463 5000

Tavistock Communications

Jos Simson/ Jessica Fontaine

+44 (0) 20 7920 3150

Tielle Communications

StéphanieLeclercq

+27 (0) 83 307 7587

 

 

Appendix 1

 

1.            Methodology:

Bulk samples of both the Groenfontein and Zaaiplaats ores (collected from old workings on each target) were crushed and processed into various size fractions at SGS, and sent for both grading analysis and QEMSCAN Particle Mineralogical Analysis (PMA), The analysis is designed to collect quantitative data on mineral abundances, distributions per size fraction, mineral associations, liberation characteristics, and grain size distributions for the minerals of interest.

 

2.            Summary and Interpretation of SGS Results

2.1.         Groenfontein Ore: This ore exhibits no liberation of the cassiterite above 1mm thus suggesting the presence of only fine-grained cassiterite in the ore. The best liberation is observed in the size fractions smaller than 212μm.

2.2.         Zaaiplaats Ore: This ore exhibits good liberation of the cassiterite through all the size fractions studied with significant liberation (>46%) above 1mm. These results suggest the presence of a wide size distribution of cassiterite grains in the ore matrix that feature clearly defined grain boundaries.

 

3.            Preliminary Metallurgical Process Routes

3.1.         Beneficiation of the Groenfontein Ore - the following process route is suggested for this ore (Figure 1):

a)         Crushing of the ore via a jaw crusher & cone crusher and screening to 100% passing 16mm (Dry crushing & screening plant).

b)        Milling of the crushing plant product stream via rod mills and ball mills to 100% passing 1mm.

c)         Screening of the milled ore via Derrick StackSizer screens to produce three size fractions:

i.     -1mm +500µm

ii.    -500µm +100µm

iii.   -100µm

d)        Recovery of the cassiterite in the 1mm +500μm size fraction via heavy mineral spirals (Spiral Battery No. 1).

e)        Recovery of the cassiterite in the 500μm +100μm size fraction via heavy mineral spirals (Spiral Battery No. 2).

f)         Re-grinding of the middlings fraction of Spiral Battery No. 1 via a ball mall operating in closed circuit with a 500μm screen:

i.     Mill product stream passing to the Derrick Stack Sizer screens in paragraph (c) above.

g)         Recovery of the cassiterite in the -100µm size fraction via a centrifugal concentrator (Falcon concentrator or Kelsey Centrifugal Jig).

h)        Upgrading of the concentrates produced in (d), (e) and (g) above via shaking tables specifically selected for each size fraction.

i.     Shaking table concentrates passed to smelter. 

 

 

3.2.         The following process route is suggested for the beneficiation of the Zaaiplaats ore (Figure 2):

a)         Crushing of the ore via a jaw crusher & cone crushers (two stages) and screening to 100% passing 4mm (Wet crushing & screening plant).

b)        Screening of the crushing plant product stream to produce two size fractions:

i.     -4mm +1mm

ii.    -1mm

c)         Recovery of the cassiterite in the -4mm +1mm size fraction via dense medium separation (DMS):

i.     The DMS concentrates passing to the smelter.

ii.    The DMS tails passing to a ball mill operating in closed circuit with a 1mm screen.

d)        Screening of the milled ore plus the 1mm size fraction ex paragraph (b)(ii) above via a Derrick StackSizer screen to produce two size fractions:

i.     -1mm +150µm.

ii.    -150µm.

e)        Recovery of the cassiterite in the -1mm +150µm size fraction via heavy mineral spirals.

f)         Recovery of the cassiterite in the -150µm size fraction via a centrifugal concentrator (Falcon concentrator or Kelsey Centrifugal Jig).

i. Upgrading of the concentrates produced in (e) and (f) above via shaking tables specifically selected for each size fraction:

ii. Shaking table concentrates passed to smelter.

 

This information is provided by RNS

The company news service from the London Stock Exchange

 

 - ENDS -

 

Notes to the editor

Bushveld Minerals Limited is a mineral development company focused on the Bushveld Iron Ore Project and the Mokopane Tin Project, both located on the northern limb of the Bushveld Complex, South Africa.

The Bushveld Iron Ore Project comprises two licenses covering 7,409 ha where a JORC compliant open-castable resource of 633 million tonnes (comprising 260 million tonnes Indicated and a further 373 million tonnes Inferred) has been established from a 4.5 km strike length. Further drilling along strike is expected to significantly add to the resource on the basis of identified strike extensions several kilometres long to the north and south of the project area with a target resource in excess of 1 billion tonnes planned. A scoping study on the project is underway for completion in Q1 2013.

The Mokopane Tin Project consists of one licence covering 13,422 ha where numerous targets for open-castable disseminated tin resources have been identified. The Company has explored and drilled one target (Groenfontein) and has short-term plans to explore a further four targets. The Company has established a JORC resource in excess of 5,000 tonnes of tin on the first target drilled, and is looking to expand the resource base by undertaking an exploration and drilling programme on other targets in the licence area as well as in areas currently under application. In the longer term, the Company intends to expand the resource base further by acquiring additional projects in the Bushveld Complex and elsewhere.

 

The Company was admitted to the AIM of the London Stock Exchange in March 2012.

The scientific and technical information contained within this announcement has been reviewed and approved by Joe van Niekerk, a metallurgical consultant to the company on tin projects. Joe is a consulting metallurgist with 33 years experience in extractive metallurgy with an emphasis on ore dressing including physical separation techniques across a broad range of minerals. 

 

Figure 1. Groenfontein Block Flow Diagram

 

http://www.rns-pdf.londonstockexchange.com/rns/4129T_-2012-12-12.pdf 


Figure 2. Zaaiplaats Block Flow Diagram

 

http://www.rns-pdf.londonstockexchange.com/rns/4129T_1-2012-12-12.pdf 


This information is provided by RNS
The company news service from the London Stock Exchange
 
END
 
 
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