Tritton

Greenfields and Brownfields Exploration at the Tritton Copper Operations (NSW)

Greenfields and Brownfields Exploration at the Tritton Copper Operations (NSW).  The Tritton tenement package in New South Wales comprises seven exploration and mining licences covering 2,160km2 of highly prospective ground for base metal deposits within the Girilambone Basin. Since modern exploration commenced in the 1980s, more than 750,000 tonnes of copper, has been discovered within the 100% Aeris-owned Tritton tenement package. Geological mapping has extended the known extents of the Budgery Sandstone unit a further 65 kilometres through the northern half of the tenement package, with the potential to extend a further 40 kilometres.

The nearby Canbelego Project (Aeris 30%) is held through a Joint Venture with Helix Resources.

Aeris’ exploration strategy within the Tritton tenement package is based on growing the operations through the extension of mineralisation at the current Mineral Resource deposits, principally at Tritton and Murrawombie, and focussing on the potential discovery of new copper sulphide deposits.

Recent greenfields exploration has been focused on the under-explored northern half of the tenement package above and east from Avoca Tank. The principal form of exploration was via the utilisation of airborne and ground-based electromagnetic (EM) survey techniques.

The EM technology is designed to detect for massive sulphide deposits to 500 metres (ground) and 300 metres (airborne) below surface. Advancements in the genetic understanding of the mineralised system have continued to focus on structural and mineralogical relationships. Copper sulphide mineralisation is considered to occur along late stage structural fabrics in regions containing secondary magnetite.

Exploration activities in FY2020 included:

  • Underground drilling at the Murrawombie deposit further extended the limits of the known mineralized envelopes, with variable quantities of sulphides intersected, culminating in the identification of three new copper sulphide lodes;
  • Completion of ground-based electromagnetic (MLTEM) surveying over each priority airborne EM anomaly within the northern half of the tenement package. Anomaly K was confirmed as bedrock conductor;
  • Completion of MLTEM surveying between the Murrawombie and Avoca Tank prospective corridor;
  • Completion of a modest drill campaign, totalling three drill holes within the Murrawombie to Avoca Tank prospective corridor – which confirmed downplunge extension of mineralisation at the Caribou Prospect; and
  • Exploration licence (EL) EL8987 was granted and covers a potential extension of Anomaly K off the current Tritton tenement package.
Tritton Tenement Package Project Map

Tritton Tenement Package Project Map

 

Regional Geology Compilation

Exploration work across the Tritton tenement package has historically been focused around the current Mineral Resource deposits. The amount of greenfield exploration further afield was historically focused, primarily along the Budgery Sandstone stratigraphic corridor between the Budgery and Avoca Tank deposits and along the Kurrajong – Birrimba magnetic complex. From 2018 onwards, there has been renewed interest in the northern half of the tenement package with the understanding that the prospective Budgery-Sandstone unit extends throughout the field, with regional mapping confirming an additional 65 kilometres and the potential for a further 40 kilometres within EL8810.

Known mineralisation discovered within the Tritton tenement package to date located proximal to the Budgery-Sandstone unit is approximately 750,000 tonnes of copper metal along a 50 kilometre section of the Budgery-Sandstone corridor.

To date, the majority of the on-ground exploration within the Tritton tenement package has been focussed within the southern half, along the prospective “Budgery Sandstone” corridor between the Budgery and Avoca Tank deposits.

Exploration of the northern part of the tenement package has been limited until the recently completed airborne EM surveys, with previous exploration limited to one airborne EM survey flown in the late 1990s. A recent review of the historical EM survey data from the late 1990s indicated it was largely ineffective in detecting concealed mineralisation below surface.

Recent regional mapping and follow-up geophysical interpretation over the northern half of the tenement package was successful in identifying the continuation of the Budgery Sandstone unit for a further 65 kilometres than originally thought. Additionally, the prospective corridor was interpreted to extend a further 40 kilometres further northwest, into an area now covered by EL 8810.

EL8810 was granted in late 2018 and is located adjacent to the north-west corner of the current Tritton tenement package. The new tenement, covering an area of  296km2, brings the total Tritton tenement package to 2,160km2, covering the known 155-kilometre strike extent of the Budgery Sandstone unit.

An initial trial airborne EM (AEM) survey was flown over selected areas of the Tritton tenement package in January 2018 to determine the effectiveness of this method in the detection of potential bedrock conductors. The survey was successful in identifying 4 new potential bedrock conductors along the northern margin of the tenement package.

A second AEM survey covering the remainder of the under-explored northern half of the tenement package (617km2– excluding EL8810) was flown in January 2019 and identified a further 25 EM anomalies, including 9 high-priority targets. The airborne EM survey was flown using the SKYTEMTM 312 EM system, which is designed and optimised for deep conductor bodies. This system enabled exploration to quickly and cost-effectively identify potential copper sulphide mineralisation.

A ground based moving loop electromagnetic (MLTEM) surveying was completed over the AEM conductive bodies.  The MLTEM survey was designed to filter out the AEM anomalies which are legitimate bedrock conductors from those which are related to noise or near surface cover responses.  One anomaly (Anomaly K) has been confirmed as a legitimate bedrock conductor

A separate ground MLTEM survey was completed within the highly prospective Murrawombie to Avoca corridor. In total, seven copper sulphide bodies have been discovered within the 7.5 kilometre strike corridor to date. A modest drill campaign was completed within the corridor after the completion of the MLTEM survey. A drillhole at the Caribou prospect intersected low grade copper mineralisation downplunge and also detected an off-hole EM conductor (Murrawombie North). Both warrant additional work.

Aeris will focus it’s exploration efforts at Tritton on the most prospective areas throughout the tenement package in FY2021. Regional surface geochemical sampling programs will be completed over high priority regions which may host either massive sulphide deposits analogous to the style of mineralisation which characterises Tritton and Murrawombie and non-conductive mineralisation styles analogous to the north-east deposit.

Anomaly K

Anomaly K prospect was first identified following the detection of a potential bedrock conductor from an airborne EM survey in December 2018.  The projected extents of the modelled conductive plate for Anomaly K extended beyond the tenement boundary. The MLTEM survey was suspended whilst an exploration licence application was submitted, with EL8987 being granted in June 2020.

A follow-up ground based Moving Loop survey (MLTEM) confirmed the presence of two potential conductive bodies over the prospect.  The larger modelled conductor with dimensions of 250 metres (strike) x 250 metres (dip) is located from 150 metres below surface. It is interpreted to dip moderately (30 to 40 degrees) south-east, which is consistent with a majority of known mineralised systems within the Tritton tenement package. Drill hole TAKD001 was targeted to intersect the bedrock conductor at approximately 200 metres down hole.

TAKD001 intersected an 18.8 metre (18.8 metre estimated true width) thick interval from 197.5 metres downhole. Sulphide textures varied between disseminations to massive sulphide bands within a chlorite altered turbidite host sequence (assays pending). Based on visual logging, sulphide minerals are predominately pyrite with lesser amounts of chalcopyrite.  Within the sulphide interval a 6.8 metre thick zone of banded massive sulphides is interpreted to be the conductive horizon detected from the various EM surveys. A Down Hole EM (DHEM) survey will now be undertaken to assist with planning a follow-up drill hole Samples from drill hole TAKD001 will be dispatched to the laboratory for analysis. Assay results are expected to be returned early in 2021.

Plan view showing location of the modelled bedrock conductors and drill hole TAKD001 at the Anomaly K prospect. Overlain on the satellite imagery is a late channel (Z direction) MLTEM image.

Tritton – Budgerygar Corridor

Tritton Deposit 

The Tritton – Budgerygar corridor is a highly prospective copper rich mineralised system. In the context of base metal deposits within the Girilambone basin, the Tritton deposit represents a very large mineralised system. The copper sulphide mineralised footprint has been traced over 1.9 kilometres down plunge based on current drilling data, and the deposit remains open down plunge.

The level of geological understanding of the Tritton deposit has increased significantly during the year as the underground development exposes more of the mineralised system. Although the Tritton deposit was discovered in the mid 1990s and mining commenced in 2004 the geological understanding is continually evolving.  In recent years the geology has changed at depth and as the mining front has exposure to more of the geology, it has also allowed a greater understanding of the mineralised system.

The deposit has transitioned from a tabular north/south trending system to an elongated east-west trending ellipsoid, with the deposit thickness increasing from a minimum of 20 metres to more than 80 metres in places. Copper grades have steadily decreased with the increasing depth. As the mineralised system has changed with increasing depth, internal high grade copper shoots have been identified within the Measured Mineral Resource classified sections of the Tritton deposit. It appears that the high-grade shoots may extend deeper within sparsely drilled sections of the deposit, with further work planned in the coming year to better define their potential to be mined.

Several drill programs have been completed targeting down plunge extensions (below 4,000m.RL level) to the Tritton mineralised system.  Notable assay results include:

  • TRGC1001 returned 21.5m @ 2.26% copper;
  • TRGC1009 returned 17.0m @ 1.57% copper;
  • TRGC1010 returned 7.0m @ 5.26% copper and 6.8m @ 1.82% copper; and
  • TRGC1011 returned 2.6m @ 2.28% copper.

TRGC1023 returned 23.4m @ 1.86% copper. Within the larger 2,000 metre (horizontal) Tritton – Budgerygar mineralised corridor there are numerous drill hole intersections peripheral to both deposits which contain elevated (+0.5% Cu) intersections over multiple metres. The sparsely drilled North Wing prospect immediately north of Tritton, is considered highly prospective and drilling is planned to target extensions to the sulphide mineralisation previously intersected.

Following a focus on geological interpretation work undertaken during FY2020, the Tritton geology model was updated to reflect the changing geology at depth below the 4,300mRL. Whilst the macro scale geometry change was clear, controls on the internal distribution of high-and-low grade copper mineralisation and their spatial continuity has taken longer to unravel.

The updated geology model provides an improved understanding of the potential grade profile below the current mining front (4,110mRL level) and the spatial location of potential higher-grade corridors. Drill coverage becomes progressively sparse down to the limit of drill coverage at the 3,850mRL level.

Importantly, the Tritton mineralised system remains open at depth with drill holes continuing to exhibit high grade and low grade copper horizons. The revised geological model will be used to assist with a FY2021 drill program designed to target extensions to the known Tritton mineralisation down plunge from current drilling. Downhole electromagnetic (DHEM) surveying will be completed on some drill holes to assist with vectoring toward mineralisation.

The Budgerygar deposit is located approximately 600 metres along strike (north) from Tritton. The mineralised system is defined by four discrete lodes which cover a footprint of 250 metres (strike) by 800 metres down plunge. An exploration access drive is currently being developed toward the deposit to provide a drill platform for resource definition drilling planned to commence in FY2021. Planned drilling off the exploration drive will target the upper extensions of all four lodes within a 30 metre vertical window from 5,250mRL to 4,900mRL.

Drilling will also target sporadic copper intersections in the footwall the Mineral Resource from historical drill holes completed in the late 1990s to early 2000’s.

Budgerygar Deposit

The Budgerygar deposit is located approximately 600 metres along strike (north) from Tritton. The mineralised system is defined by four discrete lodes which cover a footprint of 250 metres (strike) by 800 metres down plunge. An exploration access drive is currently being developed toward the deposit to provide a drill platform for resource definition drilling planned to commence in FY2021. Planned drilling off the exploration drive will target the upper extensions of all four lodes within a 30 metre vertical window from 5,250mRL to 4,900mRL.

Drilling will also target sporadic copper intersections in the footwall the Mineral Resource from historical drill holes completed in the late 1990s to early 2000’s.

 

Tritton and Budgerigar deposits showing current underground planned development and down plunge opportunities.

Murrawombie – Avoca Tank Corridor

Murrawombie

At the Murrawombie deposit, underground drilling continued throughout the year with a focus on extending the mineralised footprint further along strike and down plunge. Towards the end of 2019, underground drilling was completed targeting extensions to the Indicated Mineral Resource along strike (north) and down plunge. Drilling in both directions intersected copper sulphide mineralisation, highlighting the potential to increase the Mineral Resource base.

Drilling results announced on 27 February 2020 (refer to a previous ASX Announcement dated 27th February 2020 “Exciting Drilling Results at Murrawombie”), targeting the periphery of the main mineralised body (102 lode) and down plunge extensions beneath the Indicated Mineral Resource.  Significant assay intercepts down-plunge include:

  • 15.25m @ 3.07% Cu (MWGC509)
  • 34.70m @ 2.06% Cu (MWGC507)
  • 4.60m @ 2.63% Cu (MWGC500)
  • 17.30m @ 2.05% Cu (MWGC496)

 

Long section view showing drillhole pierce points through the Murrawombie main and emerging lobes

This drill program has extended the down plunge extents a further 50 metres beyond the June 2019 Mineral Resource outline and mineralisation remains open down plunge.

A total of 80 drill holes were completed during FY2020, with a majority intersecting sulphide mineralisation. Drilling through the main mineralised bodies (lode 102 and 108) resulted in the delineation of additional mineralisation along strike and down plunge. The majority of the drill holes were extended further into the hanging wall (HW) testing extensions / continuity to mineralisation previously intersected beyond the 102 and 108 lodes.

In total, eight drill holes were completed in the first quarter of 2021, with six focused on constraining the known northern extents of the hanging wall (HW) lodes (111, 113 and 115 lodes). The remaining two drill holes targeted down plunge extensions below the southern margin of the HW lodes. Assay results were not received for all eight drill holes by second quarter end.

The first of two deep (~1,100 metre) diamond drill holes from surface commenced in September. Both drill holes are targeting the projected down plunge continuation of the Murrawombie mineralised system, 150 metres to 200 metres below the current footprint.

Following the completion of both drill holes down-hole electromagnetic surveys (DHEM) will be completed to detect for conductive bodies within a 200 metre radius from each drill hole.

 

Long section view of the Murrawombie deposit showing pierce points through the hangingwall lodes. The planned surface drill program target area is shown by the red shaded rectangle.

Drilling through the HW horizon consistently intersected copper sulphide mineralisation. Drilling density was sufficient to enable an updated geological interpretation which delineated three new copper sulphide lodes in the HW to the main Murrawombie lodes. The HW lodes are and exciting discovery which highlights the prospectivity of the field and potential to increase the Mineral Resource base with the delineation of new sulphide bodies from additional near mine exploration.

Geological interpretation and modelling of the mineralised lodes continued during the quarter. Drillhole intersections through the HW has clearly defined multiple sulphide horizons. The main mineralised lodes appear to be pinching out at depth however the HW mineralisation is open along strike (north and south) and down plunge.

Whilst assays are pending for the majority of the drillholes completed within the quarter, results from the previous quarter have returned and include:

102 lode:

  • MWGC510 10.60m @ 2.07% copper (true thickness approx. 5m)
  • MWGC514 14.60m @ 2.43% copper (true thickness approx. 8m)
  • MWGC516 9.55m @ 2.54% copper (true thickness approx. 7.2m)

HW mineralisation:

  • MWGC513 13.30m @ 1.96% copper (true thickness approx. 8m)
  • MWGC516 6.95m @ 2.35% copper (true thickness approx. 3m)
  • MWGC516 5.80m @ 2.93% copper (true thickness approx. 0m)

Drilling will continue at Murrawombie in the coming quarter targeting down plunge extensions to the HW mineralisation. The drillholes will also test for potential extensions to the 102 lode at depth.

During FY2021, two deep surface holes (~1,000 metres each) are planned to test the interpreted down plunge continuity (~300 metres below current Mineral Resource) to the mineralised system. Underground drilling will continue to drill-test incremental extensions to the currently defined mineralised system. DHEM will be completed on both drill holes to assist with vectoring toward mineralisation.

Avoca Tank

The deposits discovered on the Tritton tenement package typically have a long down plunge extent and the same is expected to be true at the Avoca Tank deposit. Future exploration drilling of the deposit will be most efficient from an underground platform. However, to assist with feasibility studies, a small drilling program of up to 3 drill holes to test the vertical extension of the deposit is planned. This program has the aim of helping to improve the understanding of the deposit’s structural controls to optimise future underground drilling locations.

Kurrajong

The HP MLTEM survey completed over the Kurrajong prospect detected two strong bedrock conductors commencing at 400 metres below surface. The detection of the plates provided the impetus to commence a limited drill program testing the potential extents to mineralisation intersected from previous drilling at the prospect. The initial two holes (TKJD014 and TKJD015) targeted the interpreted mineralised extensions at 150 metres up and down plunge. Both drill holes intersected massive sulphides:

  • TKJD014 returned 19.4 metres @ 2.2% Cu; and
  • TKJD015 returned two intersections of 4.60 metres @ 5.1% Cu and 5.65 metres @ 2.5% Cu.

These results were encouraging enough for Aeris to extend the drill program with a further 12 drill holes completed in November 2018. The drilling program extended the limits of sulphide mineralisation to 300 metres along strike and 1,100 metres down plunge.

Within the large sulphide envelope, an exploration target was defined ranging from 3 to 4 million tonnes at 1.5% to 2.0% copper.

The Company has now commenced the process to obtain the necessary regulatory approvals to allow further drilling to occur at Kurrajong with the aim to progress the exploration target to an Inferred Mineral Resource.

Regional Geology Compilation

Regional Geology Compilation

To date, the majority of the on-ground exploration within the Tritton tenement package has been focussed within the southern half, along the prospective “Budgery Sandstone” corridor between the Budgery and Avoca Tank deposits.

Exploration of the northern part of the tenement package has been limited until the recently completed airborne EM surveys, with previous exploration limited to one airborne EM survey flown in the late 1990s. A recent review of the historical EM survey data from the late 1990s indicated it was largely ineffective in detecting concealed mineralisation below surface.

Recent regional mapping and follow-up geophysical interpretation over the northern half of the tenement package was successful in identifying the continuation of the Budgery Sandstone unit for a further 65 kilometres than originally thought. Additionally, the prospective corridor was interpreted to extend a further 40 kilometres further northwest, into an area now covered by EL 8810.

EL8810 was granted in late 2018 and is located adjacent to the north-west corner of the current Tritton tenement package. The new tenement, covering an area of 296km2, brings the total Tritton tenement package to 2,160km2, covering the known 155-kilometre strike extent of the Budgery Sandstone unit.

An initial trial airborne EM (AEM) survey was flown over selected areas of the Tritton tenement package in January 2018 to determine the effectiveness of this method in the detection of potential bedrock conductors. The survey was successful in identifying 4 new potential bedrock conductors along the northern margin of the tenement package.

A second AEM survey covering the remainder of the under-explored northern half of the tenement package (617km2 – excluding EL8810) was flown in January 2019 and identified a further 25 EM anomalies, including 9 high-priority targets. The airborne EM survey was flown using the SKYTEMTM 312 EM system, which is designed and optimised for deep conductor bodies. This system enabled exploration to quickly and cost-effectively identify potential copper sulphide mineralisation.

A ground based moving loop electromagnetic (MLTEM) surveying was completed over the AEM conductive bodies.  The MLTEM survey was designed to filter out the AEM anomalies which are legitimate bedrock conductors from those which are related to noise or near surface cover responses.

Aeris’ exploration focus on the Tritton tenement package within FY2020 is principally within the northern half of the tenement package, focusing conductive bodies detected from AEM and MLTEM geophysical surveys.

Caribou Prospect

Assay results were returned during the quarter for drillhole TCBD010. The drillhole targeted down plunge mineralised extensions at the Caribou prospect (located within the Larsens – Northeast mining province).

Drillhole TCBD010 intersected a broad zone of pyrite +/- chalcopyrite disseminations and minor stringer veins 100 metres down plunge to the known mineralised system. Copper assays over the broad interval reported 36.0m @ 0.10% Cu. Strong chlorite alteration was observed throughout the sulphide interval, which is commonly observed in close association to known mineralised systems elsewhere in the region.

Previous exploration drilling activities at the Caribou prospect intersected variable amounts of copper sulphide mineralisation with several encouraging results including:

  • TCBD007 6.0m @ 3.45% Cu (true thickness approx. 4m);
  • TLRNM006 4.7m @ 3.05% Cu (true thickness approx. 2m);
  • TLRNM002 28.8m @ 1.56% Cu (true thickness approx. 16m) including 15.5m @ 2.03% Cu (true thickness approx. 10m).

A downhole EM (DHEM) survey was completed down TCBD010. The DHEM survey detected an off-hole conductor above the drillhole, which corresponds with the mineralised zone intersected from previous drilling. The modelled plate extends further down plunge than previously modelled DHEM plates (combined total plunge extent 200 metres).

The drill results and modelled DHEM plates at the Caribou prospect are encouraging and may reflect a similar mineralised system to the Larsens deposit2 (~1Mt @ +2% Cu), located 300 metres to the west.

 

Plan view showing the airborne EM survey coverage and potential bedrock conductors through the northern extents of the Tritton tenement package.

Plan view showing the airborne EM survey coverage and potential bedrock conductors through the northern extents of the Tritton tenement package.

A modest drill campaign, totalling three drillholes was completed within the Murrawombie to Avoca Tank prospective corridor following the completion of a geological review and additional MLTEM survey data.  Two drillholes targeted geophysical anomalies, one 1.5 kilometres north west from Murrawombie and the other 500 metres south of Avoca Tank. The third drillhole targeted down plunge extensions to mineralisation at the Caribou prospect (located within the Larsens – Northeast mining province).    Previous exploration drilling activities at the Caribou prospect intersected variable amounts of copper sulphide mineralisation with several encouraging results including;

  • TCBD007 6.0m @ 3.45% Cu (true thickness approx. 4m);
  • TLRNM006 4.7m @ 3.05% Cu (true thickness approx. 2m);
  • TLRNM002 28.8m @ 1.56% Cu (true thickness approx. 16m) including 15.5m @ 2.03% Cu (true thickness approx. 10m).

Drillhole TCBD010 was drilled targeting 100 metres down plunge to the known mineralised system.  The drillhole intersected a broad zone of pyrite +/- chalcopyrite disseminations and minor stringer veins (total sulphide content <5%) over an approximate 40 metre interval (assays pending).  Strong chlorite alteration was observed throughout the sulphide interval which is commonly in close association to mineralised systems elsewhere in the region.

A downhole EM (DHEM) survey was completed down TCBD010.  The DHEM survey detected an off-hole conductor above the drillhole which corresponds with the mineralised zone intersected from previous drilling.  The modelled plate extends further down plunge than previously modelled DHEM plates (combined total plunge extent 200 metres).

The drill results and modelled DHEM plates at the Caribou prospect are encouraging and may reflect a similar mineralised system to the Larsens deposit (~1Mt @ +2% Cu), located 300 metres to the west.

The remaining two drillholes did not intersect sulphide mineralisation.  MNWD002 targeting an IP anomaly north west from Murrawombie intersected a graphitic shear at the target depth.  Drillhole TAVD002 targeted a potential MLTEM conductor south of Avoca Tank.

 

Long section view showing drillhole pierce points through the Caribou prospects.