Aeris Resources holds an exploration tenement package covering in excess of 1,800km2 over the prospective Tritton region, made up of five granted exploration and three mining leases.

 

TRITTON REGIONAL EXPLORATION OVERVIEW

Aeris Resources Limited has a number of prospective regional exploration tenements in New South Wales, Queensland and South Australia. The exploration strategy is to remain primarily focused on the Tritton Copper Operations, where the Company has an exploration tenement package covering in excess of 1,800km² over the prospective Tritton VMS (volcanic massive sulphides) field, made up of five exploration leases and three mining leases; collectively referred to as the Tritton tenement package.

The exploration plan is to test each of the volcanic complexes, looking deeper than previously, with a focus on discovering larger, Tritton-sized (10Mt+) deposits.Within the Tritton tenement package copper mineralisation is interpreted to occur in close association with volcanic complexes. Six major complexes have been identified to date: Tritton, Girilambone, Budgery, Kurrajong, Miandetta and Exley. These complexes are found within a sequence of sedimentary and volcanogenic rocks extending over a combined strike length of more than 100 kilometres.

Within a single volcanic complex it is common to find one or two large deposits and more numerous smaller deposits. A large deposit maybe 20 million tonnes such as the Tritton Deposit, while the smaller deposits are sub 1 million tonnes or up to 2 million tonnes in size. The exploration plan is to test each of the volcanic complexes, looking deeper than previously, with a focus on the large deposits.

The exploration plan is to test each of the volcanic complexes, looking deeper than previously, with a focus on discovering larger, Tritton-sized (10Mt+) deposits.

The exploration techniques and technology utilised to date have been very effective in identifying and defining copper deposits within the tenement package focusing on exploring within 250 metres from surface. This strategy has been successful in discovering more than 750,000 tonnes of copper in the southern half of the Tritton tenement package along a geological trend of approximately 50 kilometres in strike.  Importantly, the northern half of the package has had very little exploration undertaken to date.   Recent  mapping however has extended the strike length of the known geological trend by a further 65 kilometres.
 
The majority of the deposits are detectable from electromagnetic geophysical methods, which were instrumental in the discovery of the Tritton Deposit.

Aeris’ current $7.5 million greenfield exploration program includes the application of new high power electromagnetic technologies to detect mineralisation down to 500 metres below surface.  An airborne EM program conducted in the northernmost section of the tenements has identified four new anomalies for follow-up. 

BROWNFIELDS EXPLORATION

Tritton Deposit

The Aeris Board approved the development of Tritton Deeps, along with the associated construction of a ventilation shaft which was commissioned in 2017, enabling mining at Tritton to continue down to nearly 1,200 metres below surface. The  orebody remains open at depth and Aeris has identified a number of other exciting opportunities as part of its ongoing brownfields exploration at Tritton.

Tritton is located approximately 45 kilometres north-west of Nyngan in central New South Wales and is one of the largest known mineralised VMS systems in the area. A multi-phase drill program was completed in FY2016 to better define the mineralised system below 4,200mRL, known as Tritton Deeps. Theinitial drill program was designed to confirm continuity of copper mineralisation between the 4,200mRL to 4,000mRL levels. The second phase of drilling was designed to drill out the Tritton orebody to 40 metre by 40 metre drill spacing between the 4,200mRL to 4,000mRL levels and thereby increase the level of geological and grade certainty. Two drill holes were extended deeper and intersected copper mineralisation down to the 3,830mRL level (1,460 metres below surface) indicating copper mineralisation is not closed off at depth.

Sulphide mineralisation including copper sulphides, has been intersected along strike (north and south) from Tritton below the 4,500mRL level (approximately 750m below surface).  The southern extension referred to as the South Wing has been intersected over a 200m strike extent.  It remains open along strike to the south and up/down dip.  Drilling is planned to extend the mineralised footprint along strike from Tritton, with the aim to increase the Mineral Resource inventory at Tritton.

 

Tritton Mine Tenement Package

Budgerygar Deposit

The Budgerygar deposit is hosted within the Tritton stratigraphic package and located approximately 600 metres north of the Tritton deposit. The Budgerygar deposit has low grade gossanous material outcropping at surface which was mined intermittently during the early 1900s.

Mineralisation is characterised by a large pyrite dominant sulphide envelope (5 metres to 50 metres thick) striking north-south and dipping moderately east. Copper mineralisation is dominated by chalcopyrite and covers a strike length of 300 metres and traced 800 metres down dip and remains open.

 

 

Plan view of the Tritton and Budgerygar modelled copper deposits.  Drill intersections through the Budgerygar deposit are represented by coloured circles.

 

Murrawombie Deposit

The Murrawombie Deposit is located in the southern area of the Girilambone Complex. The deposit is the largest concentration of copper metal on Aeris’ tenements outside the Tritton Deposit and was previously mined in the 1990s as an open pit to access the oxide portion of the orebody for heap leach processing. The sulphide portion of the deposit was not mined at the time due to its unsuitability for heap leaching.

Mineralisation below the open pit is defined by multiple sulphide lodes that dip 50 degrees to the east. The dominant copper mineral, chalcopyrite, is typically associated with massive pyrite, with lesser disseminated pyrite. The larger sulphide lodes are continuous over 200 metres in length and extend at least 400 metre down dip. The dominant mineralised lodes remain open at depth below the 4,700mRL level (approximately 500 metres below surface) and represent an opportunity to further grow the Mineral Resource inventory. During FY2018 mining focused on level development and production down to the 4,812mRL level (390m below surface).  Refinements to the geology model continued as the level of geological understanding increased from underground exposures and grade control drilling.

 

TRITTON GREENFIELDS EXPLORATION

In July 2016, the Aeris Board approved a two year $7.5 million strategic greenfields exploration program on the Tritton tenement package, focusing on discovering large, Tritton-sized (10Mt+) orebodies.

The first stages of this program involved using high power electromagnetic (EM) geophysics technology, including moving loop EM technology (MLTEM) which is able to “see” 400-500 metres below surface, compared to the 200 metre depth of the equipment previously used on the tenement package, and airborne EM survey (VTEM-Max survey) able to cover large areas but not “see” as deep.

 

MLTEM Survey

Results from the MLTEM survey which was completed in mid 2018, detected several new bedrock EM conductors (anomalies), including two which are within 5 kilometres of the Tritton processing infrastructure, whilst also detecting the sulphide rich component of the Kurrajong prospect.

Importantly the modelled EM conductors at the Kurrajong  prospect extend below 500 metres, providing confidence the technique is successful in detecting conductive bodies to depths significantly greater than EM methods used throughout the mid-to-late 1990s.

Follow-up fixed loop EM (FLEM) surveys were completed over several EM anomalies, defined from the regional MLTEM survey, to verify the conductive response is associated with a bedrock source and more accurately constrain the spatial location and dimensions.

 

Marlin Anomaly

FLEM surveying over the Marlin EM anomaly confirmed the presence of a weakly conductive bedrock anomaly (100S – 200S). The FLEM anomaly is modelled from 60m to 90m below surface with dimensions in the order of 400m (strike) x 200m+ (dip length).  The anomaly is located within a favourable geological setting, located along strike and within a similar stratigraphic package hosting the Tritton deposit (approximately 3.5km north).

At the Marlin prospect one drillhole has been completed which intersected thick sequences of mafic volcanics with lesser turbidite sequences. Results from the drill core and subsequent downhole EM survey did not account for the EM response from the ground MLTEM survey. Further work is required to reconcile the drillhole data with the ground EM survey data.

Galaxy Anomaly

FLEM surveying over the Galaxy EM anomaly confirmed the presence of a conductive source. Modelling efforts were not able to fully resolve the signal and there is uncertainty as to whether the response is associated with a conductive bedrock source. The anomaly is located within the prospective stratigraphic corridor hosting Tritton, Budgerygar and Budgery and warrants further work.

A preliminary drillhole at the Galaxy prospect intersected several pyritic graphite shear zones which accounted for the EM response.

Kurrajong Prospect

The Kurrajong prospect is defined by a broad surface geochemical anomaly and associated historical workings. An initial shallow RC drill program completed in 1997, targeting oxide mineralisation  in the vicinity of the historical workings, returned sporadic zones of elevated copper mineralisation (+ 1.0% Cu) within broader low grade copper haloes. A second phase of drilling over the prospective area was completed between May 2012 to March 2013 and utilised down hole EM technology to assist with vectoring toward mineralisation. 

That drill program targeted down plunge extensions of the previous shallow copper mineralisation. A majority of drill holes intersected a series of stacked sulphide lenses defined by massive/banded pyrite +/- chalcopyrite and in places, stringer pyrite with lesser chalcopyrite. The mineralised system was traced from drill intercepts over 500 metre along strike and down plunge. The modelled EM conductor plates from the current MLTEM survey correlate with the higher grade massive/semi massive sulphide core which is defined from a limited number of drill holes.

Preliminary models defining the dimensions, orientation and depth below surface for the Kurrajong EM conductor were completed. The Kurrajong EM conductive response is interpreted to represent two stacked moderate strength conductors (1,500 to 2,000 siemens) positioned approximately 400 metres below surface, with dimensions in the range of 125 metres (strike) by 150 metres (depth). The modelled plates correlate favourably with the higher grade sections of the known deposit based. Both modelled plates are orientated parallel to the regional geology.

Highly encouraging results have been returned from three drillholes completed at the Kurrajong prospect in 2018.  (See announcements dated 16 May 2018 and 12 July 2018).

Not only have the assay results returned excellent copper and gold grades, but downhole EM surveys show significant off-hole conductors, inferring extension of strike, in addition to the 500m of mineralisation down dip identified in the earlier drilling program.

High grade copper mineralisation intersected in the early drill holes TKJD014 and TKJD015 included:

  • 19.4m @ 2.18% Cu, 0.30g/t Au, 7g/t Ag (TKJD014)
  • 4.6m @ 5.09% Cu, 0.79g/t Au, 17g/t Ag (TKJD015)
  • 55.65m @ 2.52% Cu, 0.20g/t Au, 6g/t Ag (TKJD015)

Importantly, the mineralisation at Kurrajong remains open in all directions.

Airborne EM Survey

During the March 2017 quarter a helicopter-borne EM geophysical survey (VTEM-Max survey), covering 977 line kilometres, was completed across the northern and southern extremities of the Tritton tenement package. The VTEM-Max survey was flown on 200 metre line spacings over three discrete areas within the Tritton tenement package. Each area is interpreted to represent along strike extensions from known stratigraphic corridors hosting the current Mineral Resource inventory and advanced deposits within the Tritton and Kurrajong Corridors. The intent of the survey was to identify conductive bedrock conductors within 300 metres from surface.

The VTEM-Max survey successfully defined multiple new EM anomalies, which require follow up work to assess their prospectivity. A majority of the EM anomalies were detected toward the northern end of the tenement package, which were interpreted to represent the northern extension of the Tritton stratigraphic corridor. Further work is required to verify whether the anomalies may represent a conductive sulphide body, however at this early stage it indicates there is considerable prospectivity within this portion of the tenement, which historically has not been explored as extensively.

REGIONAL GEOLOGY COMPILATION

The northern half of the Tritton tenement package has had very little exploration undertaken to date. Recent mapping in the northern section has identified a further 65 kilometres of strike along that geological trend, and the airborne EM program conducted in the northernmost section of the tenements early last year identified four new EM anomalies for further investigation.

In conjunction with the focused MLTEM survey within the known stratigraphic corridors, work is progressing to increase the geological understanding further afield.  A regional mapping and historical data compilation program, focusing on the structural and lithological features within the interpreted extensions of the Tritton and Kurrajong Corridors has been completed. Copper deposits discovered within the tenement package to date are localised within the Tritton and Kurrajong stratigraphic corridors. The projection of each corridor is understood through the central portion of the tenement, however beyond this their location is not well understood, predominately from poor outcrop, increased cover and paleao-channels masking bedrock trends from magnetic imagery. Importantly this area covers approximately 50 per cent of the current tenement package.

Surface outcrop exposures are limited to a series of resistant quartzite/chert units within the Kurrajong extensions and a regionally continuous sandstone unit within the Tritton Corridor, referred to as the Budgery Sandstone. The Budgery Sandstone unit is a significant marker unit which has been traced intermittently throughout the known corridor from Budgery through to Murrawombie. The unit represents a correlatable marker horizon from which the inferred stratigraphic position of the known deposits can be made. 

The regional mapping program successfully identified the prospective Tritton Stratigraphic package east of the Avoca Tank deposit through to the northern limits of the Tritton tenement package.  Identifying the prospective corridor and tracing it further 65 kilometres is very exciting.  It allows Aeris Resources to commence targeted exploration along the prospective terrain which to date has led to the discovery of approximately 750,000t of Cu metal between Budgery to Avoca Tank (50 kilometre corridor). 

 

Tritton Copper Operations - Exploration Focus FY2019

Whilst it is early stages in our revitalised greenfields exploration program at the Tritton Copper Operations, and more work is required, Aeris is highly encouraged by the results to date and hopes to build on this success in the coming year. In FY2019 exploration efforts will be focused on completing an airborne EM survey over the remainder of the northern half of the Tritton tenement package covering the additional 65 kilometres long geological trend considered prospective for copper mineralisation.

Drilling efforts will be focused at Kurrajong in light of the excellent drill results achieved from the current program.

 

Tritton region showing Aeris Resources Tritton  tenement package and prospective corridors for copper mineralised systems.  The planned MLTEM geophysical survey coverage is highlighted by shaded orange regions and completed survey areas by shaded magenta regions.  

 

Drill Hole Table

HOLE ID

FROM (m)

TO (m)

LENGTH (m)

CU GRADE (%)

TKJD007

567.0

571.0

4.0

2.46

TKJD008

572.0

578.0

6.0

3.92

TKJD012

603.0

613.0

10.0

2.43

Drill hole intersections through massive/semi massive mineralisation at the Kurrajong prospect which broadly correlates with the modelled bedrock EM conductors from the current MLTEM survey. Intersection represent down hole lengths.

 

 

Long section view of the interpreted Kurrajong mineralised envelope showing location, thickness and copper grade from drill hole intersections through the sulphide deposit.

Airborne EM Survey

During the March 2017quarter a helicopter-borne EM geophysical survey (VTEM-Max survey), covering 977 line kilometres, was completed across the northern and southern extremities of the Tritton tenement package. The VTEM-Max survey was flown on 200 metre line spacings over three discrete areas within the Tritton tenement package. Each area is interpreted to represent along strike extensions from known stratigraphic corridors hosting the current Mineral Resource inventory and advanced deposits within the Tritton and Kurrajong Corridors. The intent of the survey was to identify conductive bedrock conductors within 300 metres from surface.

The VTEM-Max survey successfully defined multiple new EM anomalies, which require follow up work to assess their prospectivity. A majority of the EM anomalies have been detected toward the northern end of the tenement package, which is interpreted to represent the northern extension of the Tritton stratigraphic corridor. Further work is required to verify whether the anomalies may represent a conductive sulphide body, however at this early stage it indicates there is considerable prospectivity within this portion of the tenement, which historically has not been explored as extensively. 

 

 

Plan view showing MLTEM results within the Tritton corridor (CH23 B field Z component). The Raven EM conductor is located north of Tritton while the Marlin EM conductor is located south of Tritton within the Greater Hermidale geochemical anomaly.