• Maiden Mineral Resource estimate reported under JORC Code 2012 edition.
• Total Inferred Mineral Resources of 41.4 Mt at 7.5% Pb, 3.5% Zn, 0.33% Cu and 178g/t
Ag at a cut-off of 2.0% Pb.
• Estimate based on 56,008 metres of historical underground sampling supported by a
diamond drilling program of 21 holes for 2,965.6 metres and a channel sampling
programme in the shallow open pit of 43 channels for 669 metres.
• Mineral Resource represents the extensive mineralised ‘halo’ around the high-grade
lodes that were historically mined underground.
• Drilling and channel sample results announced to ASX on 17 September 2017 highlight
the extensive high-grade mineralisation that occurs within the halo zone.
• The Mineral Resource estimate provides the key input to the ongoing Scoping Study
to assess an open-pit mine development strategy at Bawdwin and provide a basis for
Myanmar Government permitting.
Myanmar Metals Limited (ASX: MYL) (“MYL” or “the Company”) is pleased to advise that it has received the results of the Mineral Resource estimate completed by CSA Global. As previously reported, MYL holds an option with Win Myint Mo Industries Co. (“WMM”), the Myanmar company that holds the 38 km2 Mining Concession at Bawdwin.
The estimate is based on extensive historical channel sampling of underground exploration cross cuts supported by new diamond drilling and channel sampling data collected in 2017. The maiden JORC Code 2012 compliant Mineral Resource estimate highlights the potential of the Bawdwin Project to be redeveloped as a large-scale mining operation. The forthcoming Scoping Study will further assess this potential.
Myanmar Metals Limited’s Chairman, John Lamb, commented:
“This initial resource of over 40 million tonnes with excellent grades puts the project, the
Company and its partners in a great position to confidently move ahead with economic
evaluation and Myanmar Government permitting of a new mine development.
This resource estimate clearly demonstrates the potential of the Bawdwin deposit but it only represents the remnant high-grade and surrounding low-grade mineralisation from historical mining.
There is great potential via future exploration programs to extend the open pittable and
underground areas of the three known lodes and to discover new lodes. In other words, this resource represents only the beginning of the new Bawdwin story.”
Bawdwin Mine Background
Mining of silver at Bawdwin dates back at least the 15th Century. Development of a large
underground mine by Burma Corporation commenced in 1914 including the development of the 2.4-kilometre Tiger Tunnel and 520-metre-deep Marmion Shaft. The Tiger Tunnel at the No. 6 Level provided mine drainage and ore haulage with the Marmion Shaft providing haulage from the No. 12 Level. The mine exploited three high-grade lodes, the China, Shan and Meingtha lodes. The current underground mine consists of 13 levels at approximate 40-m intervals and is free-draining through the Tiger Tunnel.
Annual production before WW2 reached about 0.5 Mt of high-grade silver, lead, and zinc-rich ore. Ore was railed to the lead smelter at Namtu, 15 miles from Bawdwin, where lead, antimony and silver were recovered while zinc was sold in concentrate. The mine and smelter were destroyed in the war but re-opened in 1951. The mine was nationalised in 1963. Production fell progressively, reflecting depleting resources and lack of investment in development and exploration. An open pit was developed in the 1970s to exploit lower grade mineralisation but suffered from poor recoveries. All mining ceased in 2008.
Records of mining, surveying, and sampling were kept meticulously at the mine on hard-copy level and floor plans and associated survey and assay ledgers. WMM engaged Australian-led Myanmar-based Geological Services Company, Valentis Services Limited (“Valentis”), to capture this hard-copy data between November 2016 and June 2017. All data for the 12 levels has now been captured with partial capture from intermediate floor plans. This has allowed 3D modelling of mined stopes, mineralisation and geological contacts, as well as capture of historical assay data into a Microsoft Access database.
During its years of underground production, the primary exploration method at Bawdwin was via driving exploration cross-cuts into the footwall and hangingwall of the main lodes. Most underground exploration occurred above the No. 6 level, with drives at intervals of 20 to 60 metres extending from 20 to 100 metres from the main lodes and with some drives extending up to 200 metres. Underground exploration was limited from the No. 7 to 12 levels. The cross cuts were geologically mapped and channel sampled for assaying at the mine laboratory.
Limited exploration at Bawdwin was completed as part of Government-supported
programmes by the UN (UNSFP 1962-64), Canada (CIDA, 1973-74), Germany (BGR, 1973-
1976), and Australia (AMDEL, 1985-87). Drill testing of the main mineralised zone and halo was very limited, the most significant being the 10 CIDA drill holes testing the halo
mineralisation at the China Lode. The UN programme included limited underground drilling, however, all drilling programmes suffered from poor recoveries. The collar locations for the historical drilling have been acquired but assay results have not yet been obtained.
2017 Exploration Programme
In 2016, WMM commissioned Valentis to manage a programme of mapping, channel
sampling and diamond drilling. A total of 435 channel samples were collected from accessible cleaned faces in the open pit, comprising 47 individual channels for 1,790.8 metres. Twentyone (21) diamond drill holes (including two partial redrills) for 2,965.6 metres were completed between February and June 2017 by Titeline Valentis Drilling Myanmar. The current open pit at Bawdwin is approximately at the base of the partial oxidation and channel sampling largely sampled fresh sulphide mineralisation.
Drill collar and channel sampling data and results were reported in MYL’s ASX release dated 13 September 2017. Drilling and channel sampling results returned extensive intersections of high to moderate grade lead, zinc, copper and silver mineralisation. The results confirmed extensive mineralisation in the hangingwall and footwall of the mined China, Shan and Meingtha lodes, in particular in the footwall relay zone of the China Lode linking to the offset Shan Lode.
Bawdwin Mineral Resource Estimate
As part of the evaluation of the Bawdwin Project under the WMM option, CSA Global was
retained by MYL to assess the geology and resources of the project, to complete a Mineral
Resource estimate and to undertake an initial scoping study on open-pit development on the deposit. To comply with the 2012 edition of the JORC Code, CSA Global has completed a review of the geology of the project and compiled a Table 1 as required by the JORC Code.
A summary of the information used in the resource estimation follows:
Drilling and Channel Sampling
The Mineral Resource estimate is based largely on historical underground channel sampling but with support from the 2017 programme of diamond core drilling and channel sampling in the open pit. The historical sampling was completed systematically and routinely during the period of active mining at Bawdwin and samples were assayed by wet chemical methods at the mine laboratory. There are no records of QAQC procedures or analyses. Access to the sampled drives is no longer possible so check sampling cannot be undertaken. The data and associated documentation are considered adequate to support reporting of an Inferred Mineral Resource.
Additional information regarding sampling and analysis is provided in JORC Table 1 which is attached to this ASX release.
The Bawdwin deposit is hosted within an Early Ordovician volcanic and intrusive complex termed the Bawdwin Volcanic Centre. This comprises coarse volcaniclastic tuffs of the Bawdwin Volcanic Formation that interfinger with calcareous sediments of the Pangyun Formation, both intruded by co-magmatic rhyolite porphyry bodies.
The Bawdwin deposit is a structurally controlled massive to disseminated sulphide deposit hosted largely within the Bawdwin Tuff and to a lesser extent within the Pangyun Formation sediments and rhyolitic porphyry. The main controlling Bawdwin Fault zone comprises a complex northwest-trending, southwest-dipping, array of faults, splays and relays. Massive mineralisation occurs in dilational structural zones as veins and breccias, with semi-massive to disseminated sulphide mineralisation and stockwork sulphide veining occurring in the intervening silicified lithic breccia (Bawdwin Tuff).
Sulphide mineralisation at Bawdwin is characterised by argentiferous galena, sphalerite, and pyrite together with smaller amounts of chalcopyrite, covellite, tetrahedite, gersdorffite, and cobaltite. Copper mineralisation occurs with lead and zinc but also separately where it can be associated with nickel and cobalt. Sulphides are generally coarse grained in massive lodes and when disseminated in altered tuff.
The historically-mined China, Meingtha and Shan lodes lie along 4 km of strike of the Bawdwin Fault zone, with offsets by later faults. The mined lodes were probably not uniform zones of massive sulphide but zones of mineralised structures and intervening strongly mineralised breccias and stockworks. The most extensive ‘halo’ mineralisation is up to 150 metres wide in the footwall of the main China Lode. This encompasses mined stopes in the footwall of the China Lode and is characterised by high-grade veins, breccias, stockworks and shear zones and extensive zones of disseminated mineralisation associated with silicification of the lithic breccia host (Bawdwin Tuff). The zone is interpreted to reflect a relay zone extending north towards the Shan Lode where it is poorly tested by underground sampling and drilling.
A 3D model developed by Valentisincluded the Bawdwin Tuff, major faults, high-grade “lode” mineralisation and lower-grade “halo” mineralisation. The model was reviewed by CSA Global and the high-grade zones were re-modelled based on interpretation of level-plan geological and assay data, supported by recent drilling. The model was also supported by open-pit mapping and channel sampling.
Classical statistical analysis was carried out twice for the mineralised zones. The first study was carried out to meet the following objectives:
To determine a cut-off grade for interpretation of mineralisation
To assess grade distribution characteristics.
Review of the histograms and probability plots indicate that a 3.5% Pb cut-off grade is suitable for interpretation of the high-grade lodes and 0.5% Pb for mineralised halos.
The historical underground data and modern diamond drilling and pit mapping were used to develop a new interpretation of the Bawdwin deposit using Micromine software. Wireframes of the major lodes were developed based on plan view interpretation for all developed underground levels. Additionally, all wireframes were adjusted to include the results of 2017 diamond drilling and open pit channel sampling.
Major individual base metal lodes were modelled using a nominal 3.5% Pb cut-off. A “halo” zone of mineralisation enveloping the lodes was modelled with a nominal 0.5% Pb cut-off.
Volume block models were created within each defined mineralisation domain. All models were flagged according to mineralisation type and wireframe name. This flagging was subsequently used to interpolate grades separately for each body and to exclude “contamination” with grades from adjacent models. After flagging, the models for each mineralisation type were combined. Therefore, the values of some blocks were updated (overwritten) during integration. The blocks above the topographic surface were then removed.
Lead, silver, zinc and copper grades were interpolated into the empty block model using
ordinary kriging (OK). A “parent block estimation” technique was used. The OK process was performed at different search radii until all cells were interpolated. The search radii were determined following evaluation of the semivariogram parameters.
The Mineral Resource has been classified in accordance with guidelines contained in the JORC Code 2012 Edition. The Inferred Mineral Resource classification is based on drill hole sampling, open pit channel and historical underground channel sampling. Existing data is believed to be sufficient to imply but not verify geological and grade continuity due to the absence of QAQC information for the historical underground data. The Inferred classification has considered all available geological and sampling information and the classification level is considered appropriate.
Bawdwin – Next Steps
The maiden Mineral Resource estimate in accordance with the JORC Code 2012 Edition
provides the key input to the Scoping Study on development of an open cut mine at Bawdwin. The study results together with geological interpretation that is currently underway will inform the Myanmar Government permitting process and decisions on the next phase of work at Bawdwin. This is expected to include a significant drilling programme scheduled to commence in the first half of 2018.
For More Information:
John Lamb, Chairman and Chief Executive Officer
Mob: +61 (0) 400 165 078
The announcement contains certain statements, which may constitute “forward-looking
statements”. Such statements are only predictions and are subject to inherent risks and
uncertainties, which could cause actual values, results, performance achievements to differ materially from those expressed, implied or projected in any forward-looking statements.
Competent Person Statements
The Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore
Reserves (the ‘JORC Code’) sets out minimum standards, recommendations and guidelines for Public Reporting in Australasia of Exploration Results, Mineral Resources and Ore Reserves. The Information contained in this announcement has been presented in accordance with the JORC Code.
The information in this report that relates to Geology and Exploration Results is based, and fairly reflects, information compiled by Dr Neal Reynolds, who is a Member of the Australian Institute of Geoscientists. Dr Reynolds is employed by CSA Global Pty Ltd, independent resource industry consultants. Dr Reynolds has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the 2012 Edition of the ‘Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves’. Dr Reynolds consents to the inclusion in the report of the matters based on his information in the form and context in which it appears.
The information in this report that relates to Mineral Resources is based, and fairly reflects, information compiled by Mr Serikjan Urbisinov, who is a Member of the Australian Institute of Geoscientists. Mr Urbisinov is a full-time employee of independent, resource industry consultancy CSA Global Pty Ltd.
Mr Urbisinov has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the 2012 Edition of the ‘Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves’. Mr Urbisinov consents to the inclusion in the report of the matters based on his information in the form and context in which it appears.