Aeris Resources holds an exploration tenement package covering in excess of 1,800km2 over the prospective Tritton region, made up of six 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 six exploration leases and three mining leases; collectively referred to as the Tritton tenement package.

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 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 yielded more than 750,000 tonnes of copper. A majority of the deposits are detectable from electromagnetic geophysical methods, which were instrumental in the discovery of the Tritton Deposit.

BROWNFIELDS EXPLORATION

Tritton Deposit

The Aeris Board approved the development of Tritton Deeps in FY2017, along with the associated construction of a ventilation shaft and installation of exhaust fans, enabling mining at Tritton to continue down to nearly 1,200 metres below surface, with the orebody remaining open at depth. Aeris has identified a number of other exciting opportunities as part of the focus on brownfields exploration in FY2018.

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. The initial 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 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. During FY2017 no further exploratory drilling was completed. Drilling activities during the reporting period were focused on grade control delineation below the current mining front (4,165mRL-4,125mRL).

Tritton Mine Section View

Budgerygar Deposit

The Budgerygar Deposit is hosted within the Tritton stratigraphic package and located approximately 600 metres north of the Tritton Deposit. The 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) 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 throught the Budgergary 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 (about 500 metres below surface) and represent an opportunity to further grow the Mineral Resource inventory. During FY2017, mining focused on level development with intermittent production from stoping. Refinements to the geology model continued as the level of geological understanding increased from underground exposures.

 

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 Tritton-sized orebodies of more than 10 million tonnes.

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.

The MLTEM program commenced in December 2016 and was 50 per cent completed by the end of the FY2017. Results to date from the MLTEM survey have 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 Kurrajong 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.

The airborne EM survey was completed in the March quarter of FY2017 on the northern and southern extremities of the Tritton tenement package, with the latest results also identifying numerous new anomalies, which now require further investigation.

Whilst it is early stages in our revitalised greenfields exploration program 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.

REGIONAL GEOLOGY COMPILATION

In conjunction with the focused MLTEM survey within the known stratigraphic corridors, work is being undertaken to understand the geological architecture further afield. During FY2017, a regional mapping and historical data compilation program commenced, focusing on the structural and lithological features within the interpreted extensions of the Tritton and Kurrajong Corridors. 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.

The intent is to identify and trace the outcropping lithological units within the favourable horizons along strike to identify and project the prospective corridors and provide a more detailed understanding of the structural framework.

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 will result in a more detailed geological interpretation, which will be used in conjunction with historical data (geophysics, surface geochem and geological interpretations) to refine prospective areas for follow up work, including the anomalies identified from the VTEM-Max survey.

 

 

 

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.  

 

Bedrock EM conductors (Kurrajong Corridor)

Finalised MLTEM results over the Kurrajong complex is constrained to the north-east corner of the survey area.  The survey has detected two EM conductors, the already known Kurrajong Prospect and the McPhersons geochemical anomaly (McPhersons EM Anomaly).

Plan view of the north-east corner of the Kurrajong complex showing MLTEM results (CH25 B field Z component) overlain on a magnetic 2VD image (black and white image). 

Anomalous copper surface geochem contours are also displayed.

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.  The 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 has been 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 and McPhersons EM conductors has been 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 on current drill hole information. Both modelled plates are orientated parallel to the regional geology.

 

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 lenghts.

 

 

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

 

Recent surface mapping within the Kurrajong complex confirms the broad stratigraphic units identified at Kurrajong trend toward the McPhersons EM Anomaly. Both the Kurrajong Prospect and the McPhersons EM Anomaly are located within or adjacent to basic – intermediate volcanic units which manifest as magnetic highs.  The McPhersons bedrock EM conductor is of similar size and conductance to the Kurrajong modeled plates.

Preliminary modeling of the McPhersons EM response defined a moderate strength conductive plate (1000 to 2000 siemens) with dimensions in the range of 200 metres (strike) x 150 metres (depth) from 350 metres to 400 metres below surface.

A fixed loop EM (FLEM) survey will be completed over each EM conductor to refine the modeled plate spatial location and dimensions further to assist with prospect ranking and drill targeting. Modeled EM plate parameters (size/signal strength) will be considered in conjunction with the geological setting (stratigraphy/proximity to magnetic embayments) and surface geochemistry results. EM anomalies positioned higher on the prospectivity ranking will be prioritised for follow up exploration work including a first pass drill program.  

 

Bedrock EM Conductors (Tritton Corridor)

MLTEM results to date within the Tritton corridor are centralised around Tritton, extending 9 kilomters south and 5 kilometers north of Tritton.  Two EM conductors have been identified.  The Raven EM Anomaly is located 2.5 kilometers north of Tritton and is interpreted to occur within the same stratigraphic package hosting the Tritton deposit.  The Marlin EM Anomaly is located 3.5 kilometres south of Tritton within the extensive Greater Hermidale geochemical anomaly which extends periodically over a 5 kilometers strike length.  A number of small highly conductive cover units occur throughout the area shown as magenta/red shaded regions.

Preliminary modelling has been completed on both the Raven and Marlin EM conductors to define their spatial location and dimensions. The Raven conductive model is defined as a large 500 metre (strike) x 100 metre (depth) plate from 350 metre to 400 metre below surface. The plate is orientated parallel to the regional trend and dipping steeply to the west. The Marlin EM response is defined by a 300 metre (strike) x 300 metre (depth) plate located approximately 200 metre below surface. The interpreted orientation is striking north-east which is oblique to the interpreted regional trend (north-south).

A fixed loop EM (FLEM) survey will be completed over each EM conductor to refine the modeled plate spatial location and dimensions further to assist with prospect ranking and drill targeting. Modeled EM plate parameters (size/signal strength) will be considered in conjunction with the geological setting (stratigraphy/proximity to magnetic embayments) and surface geochemistry results. EM anomalies positioned higher on the prospectivity ranking will be prioritised for follow up exploration work including detailed a first pass drill program.  

Airborne EM Survey

During the March 2017 quarter a helicopter-borne EM geophysical survey (VTEM-Max survey), covering 977 line kilometres, was also conducted across the northern and southern extremities of the Tritton tenement package. The VTEM-Max survey was flown on 200 metres 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/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 results from the VTEM-Max survey were finalised during the March FY2017 quarter with multiple EM anomalies being identified, 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.