Havieron - Results of New Geophysical Models

RNS Number : 6081I

Greatland Gold PLC

27 November 2018

 

27 November 2018

Dissemination of a Regulatory Announcement that contains inside information according to REGULATION (EU) No 596/2014 (MAR).

Greatland Gold plc

("Greatland" or "the Company")

Havieron - Results of New Geophysical Models  

New 3D gravity and magnetic models indicate potential for mineralisation at Havieron to extend further than previously expected to depths in excess of 1,200 metres

Greatland Gold plc (AIM:GGP), the precious and base metals exploration and development company, is pleased to announce the results of the latest geophysical modelling at its 100% owned Havieron licence in the Paterson region of Western Australia.

Geophysical models have been a fundamental component in the discovery of exceptional mineralisation at Havieron and these models are constantly being refined with the latest petrophysical information collected from wireline (downhole) logging and measurements taken from drill core. Further to the announcement of 14 February 2018, new 3D geophysical models of the Havieron target have been produced and are reported here.

Highlights of New Geophysical Models:

·     New 3D gravity and magnetic models indicate that there is potential for mineralisation at Havieron to extend from approximately 400m below surface to depths in excess of 1,200 metres below surface;

·     Modelling of gravity data outlines a large irregular shaped body, some 300m across, from approximately 400m below surface (top of basement) to 1,200m below surface with an overall subvertical attitude;

·     Modelling of magnetic data defines a single, discrete, high amplitude elliptical shaped body that is steeply dipping (subvertical) toward the south east with a depth extent from around 800m below surface to approximately 1,400m below surface, but the body may continue beyond 1,400m as this is the current limit of data resolution;

·     A comparison of 3D gravity and magnetic models shows an approximate 500m vertical and 200m lateral offset between the causative bodies, which may be important for targeting if Havieron displays affinities with an iron-oxide-copper-gold ("IOCG") system.

Gervaise Heddle, Chief Executive Officer, commented:  "We are very excited by the results of the latest geophysical modelling which suggest that Havieron has the potential to represent a significantly larger mineralised system than we previously expected. Our excellent recent drilling results only tested to approximately 800 metres below surface and elevated gold and copper persisted to the end of several holes, suggesting that mineralisation continues at depth below the current limit of drilling.

"Havieron is a conspicuous 'bulls-eye' magnetic anomaly, as seen in airborne data sets. There are more than twenty magnetic anomalies similar to that observed at Havieron within Greatland's Paterson licences and, in light of the exceptional mineralisation at Havieron, these represent compelling regional exploration targets."

Greatland's drilling campaigns at Havieron have yielded excellent results to date, including:

·     121m at 2.93g/t gold and 0.23% copper from 497m (HAD001).

·     21m at 3.79g/t gold 0.44% copper from 418m (HAD003).

·     Combined intercept of 275m at 4.77g/t gold and 0.61% copper, including an upper zone of 118m at 3.08g/t gold and 0.84% copper from 459m and a lower zone of 157m at 6.04g/t gold and 0.44% copper from 660m (HAD005).

Greatland's second drilling campaign at Havieron is ongoing and further analytical results are awaited.

A regional map showing the Havieron licence area with regional targets and adjacent landholdings can be found at: http://greatlandgold.com/paterson/ 

Overview of Paterson Project, Havieron licence and Geophysical Modelling

The Company's Paterson project, comprising the Havieron, Black Hills and Paterson Range East licences, is located in the Paterson region of northern Western Australia. The three licences collectively cover more than 385 square kilometres prospective for IOCG type deposits and Telfer style gold deposits.

The Paterson region hosts several large gold and copper deposits such as Telfer and Nifty. The region has been subject to more recent exploration which has outlined several other deposits including Magnum (Au), Calibre (Au), O'Callaghans (W, Cu) and Maroochydore (Cu).

The region is remote, however infrastructure is good with several operating mines, roads, formed tracks and rail networks nearby which branch out from the regional industrial hub of Port Hedland 500km to the west.

The Paterson Province is the northern portion of the Proterozoic Paterson Orogen. More recent exploration throughout several Proterozoic Orogens within the western parts of the Australian continent has resulted in the discovery of the large Tropicana gold deposit and the large Nova nickel-copper deposit. Globally these Proterozoic Orogens are highly prospective for large deposits and are often under-explored.

Alteration and mineralisation of those targets which have been drill tested at Havieron and Paterson Range East display affinities with IOCG-type deposits. Examples of these are the large Olympic Dam and Ernest Henry deposits in central and eastern Australia.

Initial airborne data outlined the Havieron target as covering approximately 1,000m x 1,000m. Depth to top of target is around 400m with these depths easily achieved with modern drilling equipment. Historically only six drill holes were completed by Newcrest between 1991 and 2003, all of which intersected significant hematite alteration and gold, plus copper anomalism. Thick lower grade zones of gold and copper were intersected and gold grades within these peaked at 15.4g/t and copper to 2.5%. The drill hole spacing was broad and the core of Havieron therefore represented an immediate resource definition drilling target.

Following a review of regional geophysical and geochemical data over the Paterson project approximately 50 IOCG-like targets were identified in the broader region, with around half in ground held by Greatland. The setting of these licences is on the western margin of a Proterozoic basin which ranges in depth from less than 100m below surface to more than 400m below surface. Basement rocks of the basin are predominantly calcareous rich sandstones intruded by several late stage granitic bodies exploiting basin margin faults which have also provided a focus for ore fluids. Historically, several of these targets were subject to initial first-pass work and show promise at hosting mineralisation as seen at Havieron. The geophysical signature of these targets is very similar to that at Havieron. Basement rocks do not outcrop and Greatland intends to employ modern geophysical and geochemical methods to define targets prior to drill testing.

MMI sampling and ground gravity over the Havieron target was completed in late 2017 at an initial sample and station spacing of 200m x 200m. Gravity results confirmed a north west structural trend of basement carbonate sediments which is mirrored by the surface MMI response. Clusters of elevated gold, silver, arsenic, copper and iron in MMI results are proximal the peak co-incident gravity and magnetic response. An elevated MMI response in pathfinder elements (cerium, lanthanum, uranium and lead) to the immediate SE of Havieron suggests primary basement mineralisation may be present along strike in a structural contact for up to 1.5 kilometres. Peak MMI responses over Havieron were 4ppb silver, 70ppb arsenic, 25ppb gold, 834ppb cerium, 710ppb copper, 53ppm iron, 284ppb lanthanum, 860ppb lead and 112 ppb uranium. Elevated pathfinder elements detected by the MMI survey support the view that Havieron is an IOCG-like system.

Initial forward modelling of detailed aeromagnetic data (50m line spacing and 40m mean terrain clearance) and detailed ground gravity data (100m x 100m and 100m x 200m station spacing) over the Havieron target was completed in February 2018 by independent geophysical consultants. Results of forward modelling defined a primary body approximately 600m x 600m across with a depth extent from 400m to 900m below surface. Modelled bodies were constrained to known physical rock properties available at the time.

In April and May of 2018, Greatland carried out its maiden drill campaign at the Havieron target completing four vertical core holes (HAD001-004) for a total of approximately 2,400m of drilling. Greatland's drill locations were designed to intersect the mineralised system at Havieron near to historical drill holes HAC9101 and HAC9201. Newcrest's historic drill holes HAC9101 and HAC9201 were vertical and drilled to depths of 533m and 528m respectively. Significant results were returned including 121m at 2.93g/t gold and 0.23% copper from 497m, including 11.5m at 21.23g/t gold and 0.67% copper from 568.5m (HAD001) and 21m at 3.78g/t gold and 0.44% copper from 418m, including 1m at 29.12g/t gold and 0.4% copper from 428.5m (HAD003).

The Company re-commenced drilling at Havieron in September 2018 with the intention of completing approximately 6,000m of drilling. The first hole of the new program (HAD005) was sited 200m west of HAD001 and angled at 70 degrees toward grid east. HAD005 penetrated the Permian cover sequence to 459m before immediately entering the mineralised Proterozoic target sequence. HAD005 returned an overall intercept of 275m at 4.77g/t gold and 0.61% copper (1,581 metre grams gold equivalent*) from an upper zone of 118m at 3.08g/t gold and 0.84% copper from 459m, and a lower zone of 157m at 6.04g/t gold and 0.44% copper from 660m (as reported to market 19 November 2018), separated by an apparently unmineralised mafic intrusion. Other metals are present in the system including silver to 211g/t, zinc to 5.9% and lead to 12% (HAD005). Drilling is continuing.

Geophysical models have been a fundamental component in the discovery of exceptional mineralisation at Havieron and these models are constantly being refined with the latest petrophysical information collected from wireline (downhole) logging and measurements taken from drill core. New 3D geophysical models of the Havieron target have been produced and are reported here.

Detailed magnetic, density and gravity data from several sources were used to generate new 3D geophysical models of the Havieron target. More than fifteen inversions were run with varying parameters and several inversion methods were used for comparison. Optimal models were selected and output included block models of magnetic susceptibility and density, 3D iso-surfaces, elevation and depth slices, gridded sections and quality control information.

Results of modelling of gravity data outline a large irregular shaped body, some 300m across, from approximately 400m below surface (top of basement) to 1,200m below surface with an overall subvertical attitude. Result of modelling of magnetic data define a single, discrete, high amplitude elliptical shaped body that is steeply dipping (subvertical) toward the south east with a depth extent from around 800m below surface to approximately 1,400m below surface, but the body may continue beyond 1,400m as this is the current limit of data resolution. When 3D gravity and magnetic models are compared there is a +500m vertical and +200m lateral offset between the causative bodies. This observation can be important for targeting if Havieron has IOCG-like affinities.

Existing drill holes have only tested to approximately 800m below surface; elevated gold and copper results persisted to end of several holes suggesting the mineralisation continues at depth below the current limit of drilling. The results from recent drilling demonstrate the presence of very high grades of gold and copper at Havieron, and when considered in conjunction with geophysical models, the potential large scale of the mineralised system at Havieron is apparent.

Havieron is a conspicuous 'bulls-eye' magnetic anomaly, as seen in airborne data sets, with an amplitude of approximately 100nT. There are more than twenty magnetic anomalies similar to that observed at Havieron within Greatland's Paterson licences and, in light of the exceptional mineralisation at Havieron, these represent compelling regional exploration targets.

Additional information on the Paterson project (Havieron, Black Hills and Paterson Range East licences) can be found on the Company web site at www.greatlandgold.com/projects.

Competent Person: 

Information in this announcement that relates to exploration results is based on information compiled by Mr Callum Baxter, a director of Greatland Gold plc, who is a member of the Australasian Institute of Mining and Metallurgy and Australian Institute of Geoscientists. Mr Baxter has sufficient experience relevant to the style of mineralisation and type of deposit under consideration and to the activity which has been undertaken to qualify as a Competent Person as defined by the 2012 Edition of the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (the JORC Code) and under the AIM Rules - Note for Mining and Oil & Gas Companies. Mr Baxter consents to the inclusion in the announcement of the matters based on their information in the form and context in which it appears. 

Enquiries:

Greatland Gold PLC

Gervaise Heddle/Callum Baxter

Tel: [phone]

Email:  [e-mail]

www.greatlandgold.com

SPARK Advisory Partners Limited (Nominated Adviser)

Mark Brady/Andrew Emmott/James Keeshan

Tel: [phone]

SI Capital Limited (Broker)

Nick Emerson/Alan Gunn

Tel:  [phone]

Luther Pendragon (Media and Investor Relations)

Harry Chathli/Alexis Gore

Tel: [phone]

Notes for Editors:

Greatland Gold plc (AIM: GGP) is a London listed natural resource exploration and development company with a current focus on gold, copper and nickel exploration projects.  

The Company has six main projects; four situated in Western Australia and two in Tasmania.  All projects are 100% owned by Greatland.

Greatland is seeking to identify large mineral deposits in areas that have not been subject to extensive exploration previously.  It is widely recognised that the next generation of large deposits will come from such under-explored areas and Greatland is applying advanced exploration techniques to investigate a number of carefully selected targets within its focused licence portfolio.

The Company is also actively investigating a range of new opportunities in precious and strategic metals and will update the market on new opportunities as and when appropriate.

 

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