2015 broken hill resources investment symposium - bht minerals - mark dugmore
TRANSCRIPT
Discovering the NEXT Broken Hill Mark Dugmore
Broken Hill Symposium 27 May 2015
The in-‐ground value of the (pre-‐mined, pre-‐eroded) Broken Hill deposit at current metal prices is
AUD$165 Billion
Deposit of NaLonal Interest -‐ Town of NaLonal Heritage
Assumes: 300Mt @ 148 g/t Ag, 18.5% combined Pb+Zn. Source: O’Brien et al, 2015
§ Broken Hill is among the great ore deposits of the world
§ Cannington is the world’s largest primary producer of silver ~30 Moz annually
Broken Hill-‐type Deposits. A big prize!
Mt Ag g/t
Zn % Pb %
Ag Moz
Zn mt
Pb mt
Broken Hill 300 148 8.5 10.0 1,430 26 30
Cannington 44 538 4.4 11.6 760 2 6
Only Five ‘Large’ BHT Mines around the World
Large ‘single’ deposits dominaLng a district are the norm. Lower discovery risk exists in NEW districts.
SchemaLc Broken Hill Type Environment
Host quartzofeldspathic gneisses, minor amphibolite
*Fe-‐Mn-‐Ca-‐rich ‘iron fm’
Silica ± garnet, sillimanite, K-‐feldspar
Si altera>on, thin exhalites ± garnet, gahnite
Bif photo courtesy Steve Walters
K/Na > 10. Whole rock Pb to 300ppm
500m
How do you airact a BHT!
Follow the Eastern Cratons Margin § BHT deposits occur on the E edge of the Precambrian
§ IdenLficaLon of a NEW terrane is essenLal for a new discovery
§ Woodmurra is a NEW terrane
Woodmurra
MagneLcs show the Craton Margin
§ Inferred ‘pop-‐up’ block of Broken Hill Gp equivalent
§ Leading, E edge of craton -‐ magneLcally acLve
§ PaleoProt to MesoProt metamorphic terrane
Woodmurra
Olympic Dam
Broken Hill
Woodmurra Project -‐ Geology
Outcrop (to Sth of project) § Paleoprot volcano-‐sedimentary package § Age ≡ Lower Eastern Succession (??? top of Lower Willyama Supergroup)
§ StraLgraphically below BH & Cannington
Drillholes (to SE of project)* § MetasomaLsed qfs gneiss/amphibolite § Ca-‐Mn-‐Fe-‐P-‐F rich assemblages
*
Geophysicists ONE (1) – Geochemists NIL (0)
MagneLcs – Broken Hill • Lower, magneLc oxidised felsic-‐
dominant package
• Upper, reduced metasediment-‐dominant package (mag quiet)
• ProspecLve ‘TransiLon Sequence’ – in between – DisLncLve extensive linear
responses -‐ amphibolites
– Short strike length Mn-‐P ‘bif’
Broken Hill Main Lode
Cannington TMI-‐RTP & Falcon Airborne Gravity 3,000 m
Source: Witherly & Mackee, 2015
TMI AGG
• Overall low magneLc host package
• MagneLc, short strike length features with indicaLons of structural complexity
• Cannington ore directly associated with magneLte
§ Broken Hill & Cannington lie near flank of a large gravity high
§ Major ‘gravity gradients’ evident
§ Woodmurra shows similariLes
Gravity – Flanks of Highs are Very Important Cannington
Broken Hill Main Lode
Images at same scales
Woodmurra
Woodmurra Project –magneLcs • Lower, magneLc
package ?quartzo-‐feldspathic-‐rich
• ProspecLve ‘transiLon’ package with short-‐strike-‐length (bif?) and disLncLve linear (amphibolite?) features
• ‘Feature-‐deficient’ upper, ?metasediment-‐dominated package
Woodmurra Project – gravity • Dense host package
• ConcentraLon of amphibolites ???
• SpaLally associated with max development of BHT mineralisaLon and lode marker horizons at BH
§ Integrate geophysical data from SA Gov’t-‐funded iniLaLves.
§ Regional magneLcs used to define structure, favourable lithostraLgraphy and possible direct targets.
§ OLD technology (aeromagneLcs) in a NEW terrane will work.
§ Drill a range of short strike length magneLc anomalies.
§ Aim to i/sect Pb-‐Mn-‐P-‐F anomalous ‘bif’ proximal to ore.
Woodmurra Project – Strategy under cover
§ IdenLficaLon of NEW terrane essenLal for discovery of a BHT deposit
§ NEW high grade Proterozoic metamorphic terrane ranked highly as interpreted NW extension of Broken Hill Block on craton margin
§ MagneLc (short strike length & ‘boat-‐shaped’ anomalies) and gravity seung (large dense) similar to Broken Hill & Cannington
§ Apparent BHT ‘alteraLon’ / ‘unusual’ lithologies in previous drilling
§ Outcrop age equivalent to sequence below Cannington & BH
§ Successful PACE Discovery Drilling 2015 grant
Woodmurra Project – Technical Summary
Reliable Team Required
BHT Minerals Pty Ltd was incorporated in 2014 to specifically explore for giant Broken Hill-‐type (BHT) base-‐metal deposits within Australia.
Who Are BHT Minerals?
Dr Douglas Haynes Formally Chief Geologist WMC, BHP/BHPBilliton. Key member of discovery teams on Olympic Dam, Ernest Henry, Kamoa.
Bob Skrzeczynski Formally ExploraLon Manager BHP Cannington discovery.
Mark Dugmore Formally ExploraLon Manager BHP, Global Base Metals.
