BKM Copper Project - Long Column metallurgical tests confirm previous positive results

Asiamet Resources Limited ("ARS" or the "Company") is pleased to announce positive results from the column leach test work being undertaken as part of the Bankable Feasibility study on the Beruang Kanan Main ("BKM") copper deposit.

Following a 270-day leach cycle, metallurgical results obtained from the long column (6-metre) programme, support the results previously reported in the short column test work (refer ARS news release 19 December 2017). Results confirm the design basis being utilised for the leaching, solvent extraction and electrowinning facilities and provide critical process plant design inputs for the BKM feasibility study.

Key highlights include:

  • Soluble copper recoveries from the coarse crush size (P80=19mm) ranged from 72% to 81% (%Cusol) for the dominant material types defined at BKM. These recoveries represent a 4% improvement, on average, over the recoveries obtained from the short column programme.
  • The long column results confirm the expectation that utilising a finer crush size will deliver recoveries of 80% to 85% (%Cusol) for the dominant material types, as observed in the short column programme.
  • The majority of the soluble copper, as determined by the sequential copper analysis, was recovered. The soluble copper present in the residual (post-leaching) material for most columns was less than 0.15% Cusol.

Background

Asiamet completed a 122-hole Resource evaluation drilling programme as part of the BKM Feasibility Study. The results of this Resource evaluation were announced on 28 June 2017, with a supporting technical report filed with SEDAR on15 August 2017.

As part of this programme, several holes were drilled throughout the BKM deposit to collect representative samples of various material types and grades for detailed metallurgical test work. From these samples, six composites were prepared and a total of 20 columns, comprising 12 short columns (2-metre) and 8 long columns (6-metre), were operated at the CORE Resources laboratory, in Brisbane, Australia. Figures 1 and 2 show the loaded short and long columns at the start of the leaching programme. Results from the short column programme were reported on 19 December 2017.

Copper recoveries from the short and long column test work programme are in line with expectations and confirm that the copper minerals in the BKM deposit are amenable to heap leaching. Table 1 summarises the results for each of the columns.

The long columns predominantly tested material at the coarse crush size (P80 of 19mm). However, based on the leach column performance to date, and supported by preliminary geotechnical and hydrodynamic studies currently being undertaken (HydroGeoSense metallurgical test work programme), the finer crush size (P80=12.5 mm) is the preferred design basis for the BKM Copper Project. 

The long columns achieved a leach solution flux of 4 to 6kL/tonne. This leaching efficiency is generally in line with results achieved in secondary copper sulphide, heap leach operations globally. Acid generation characteristics exhibited in the long columns indicate a neutral to low acid generating environment (<5kg/t) is likely over the leach cycle, which provides a positive basis for lower operating costs.

Ongoing Metallurgical Testing

The leach column test work provides key design criteria for the leaching, solvent extraction and electrowinning facilities that will be designed as part of the BKM Feasibility Study. The outcomes are also a key input into the mine optimisation and project evaluation elements of the study.

An additional round of column test work is being undertaken to provide further information to support production optimisation and value improvement activities for the BKM Copper Project. This additional test work will also provide key input data for ramp-up and early mine life stages of the operation.

The detailed chemical characterisation from the leaching test work programme, when combined with the hydrodynamic testing programme, which is being conducted at the world leading HydroGeoSense (HGS) facility in Arizona, will provide critical information for the BKM Feasibility Study and to establish the leach recovery targets for the operation. Metallurgy data generated from both programmes will allow the project team to develop a robust and optimised set of design criteria for the heap leach pads and overall process engineering work.

Peter Bird, Asiamet's Chief Executive Officer commented:

"Results of the long column test work provide critical process plant design inputs for the BKM feasibility study and as such it is very pleasing to report results that are in line with our expectations and that further improvement in recoveries is anticipated from applying finer crush size. The Feasibility Study remains on track for delivery by the end of H1 2018 and we will continue to communicate ongoing results as they become available. The BKM Project remains extremely well positioned as one of the few advanced new copper projects moving towards production against a backdrop of a projected net short supply balance and rising copper prices."

Qualified Person

Data disclosed in this press release have been reviewed and verified by Mr David Readett, of Mworx Pty Ltd, who is a Chartered Professional Metallurgical Engineer (CP(Met)) and a Fellow of the Australian Institute of Mining and Metallurgy (AusIMM). Mr Readett has sufficient experience which is relevant to the style of mineralisation and processing methods under consideration and to the activity which he is undertaking to qualify as a Competent Person for the purposes of the AIM Rules.

ON BEHALF OF THE BOARD OF DIRECTORS

Peter Bird, Deputy Chairman and CEO

For further information, please contact: 

-Ends-

Peter Bird

Deputy Chairman and CEO, Asiamet Resources Limited
Telephone: +61 43 887 1995
Email: [email protected]

Tony Manini
Executive Chairman, Asiamet Resources Limited
Telephone: +61 43 887 1995
Email: [email protected]

FlowComms Limited
Sasha Sethi
Telephone: +44 (0) 7891 677 441
Email: [email protected]

Asiamet Resources Nominated Adviser
RFC Ambrian Limited
Andrew Thomson / Stephen Allen
Telephone: +61 8 9480 2500
Email: [email protected] / [email protected] 

Optiva Securities Limited
Christian Dennis 
Telephone: +44 20 3137 1903
Email: [email protected]securities.com

This news release contains forward-looking statements that are based on the Company's current expectations and estimates. Forward-looking statements are frequently characterised by words such as "plan", "expect", "project", "intend", "believe", "anticipate", "estimate", "suggest", "indicate" and other similar words or statements that certain events or conditions "may" or "will" occur. Such forward-looking statements involve known and unknown risks, uncertainties and other factors that could cause actual events or results to differ materially from estimated or anticipated events or results implied or expressed in such forward-looking statements. Such factors include, among others: the actual results of current exploration activities; conclusions of economic evaluations; changes in project parameters as plans continue to be refined; possible variations in ore grade or recovery rates; accidents, labour disputes and other risks of the mining industry; delays in obtaining governmental approvals or financing; and fluctuations in metal prices. There may be other factors that cause actions, events or results not to be as anticipated, estimated or intended. Any forward-looking statement speaks only as of the date on which it is made and, except as may be required by applicable securities laws, the Company disclaims any intent or obligation to update any forward-looking statement, whether as a result of new information, future events or results or otherwise. Forward-looking statements are not guarantees of future performance and accordingly undue reliance should not be put on such statements due to the inherent uncertainty therein.

This announcement contains inside information as stipulated under the Market Abuse Regulations (EU) no. 596/2014 ("MAR").


Table 1: Short and Long Column Leaching Recovery Summary

Column IDColumn Length Crush Size
(P80)
Recalculated
Head

(%CuTot)
Recalculated
Head Soluble

(%CuSol)
Total Cu
Recovered (%)
Soluble Cu
Recovered
(%)
1 2-metres 12.5mm 0.48 0.37 68.8 88.5
2 2-metres 19mm  0.51 0.39 62.0 81.5
3 2-metres 12.5mm 0.58 0.36 49.3 79.4
4 2-metres 19mm 0.54 0.33 45.4 72.9
5 2-metres 12.5mm 0.66 0.53 70.2 86.4
6 2-metres 19mm  0.57 0.46 58.6 73.8
7 2-metres 12.5mm 0.75 0.54 55.7 76.9
8 2-metres 19mm 0.69 0.51 51.6 69.8
9 2-metres 12.5mm 0.75 0.60 65.5 82.1
10 2-metres 19mm  0.76 0.58 55.6 72.4
11 2-metres 12.5mm 0.38 0.33 62.4 73.3
12 2-metres 19mm 0.35 0.30 57.2 66.8
13 6-metres 19mm 0.46 0.35 59.9 79.0
14 6-metres 19mm 0.59 0.39 49.7 75.5
15 6-metres 19mm 0.64 0.52 66.8 81.3
16 6-metres 19mm 0.79 0.57 53.9 73.9
17 6-metres 19mm 0.75 0.60 58.6 73.3
18 6-metres 19mm 0.76 0.61 58.9 73.1
19 6-metres 12.5mm 0.37 0.32 60.2 71.6
20 6-metres 12.5mm 0.35 0.30 63.3 74.3


Notes: 
All columns were 150 mm in diameter
Assays were completed for the residual material from the six (6) long columns. The detailed diagnostic analytical procedures, including sequential copper assays developed for the BKM mineralisation, has allowed for head grades to be verified through mass-balance calculations for each column. These calculations have been utilised to evaluate recoveries of total copper (%CuTot) and soluble copper (%Cusol) for each column.
 


Figure 1: Short Columns loaded and under leach at CORE Laboratory 


Figure 2: Long Columns being loaded at CORE Laboratory


Glossary of Technical Terms

“anomaly or anomalous” something in mineral exploration that geologists interpret as deviating from what is standard, normal, or expected.

“assay”
The laboratory test conducted to determine the proportion of a mineral within a rock or other material. For copper, usually reported as percentage which is equivalent to percentage of the mineral (i.e. copper) per tonne of rock.
“azimuth” the “compass direction” refers to a geographic bearing or azimuth as measured by a magnetic compass, in true or magnetic north.
“bornite” Bornite, also known as peacock ore, is a copper sulphide mineral with the formula Cu5FeS4.
“breccia” Breccia is a rock classification, comprises millimetre to metre-scale rock fragments cemented together in a matrix, there are many sub-classifications of breccias.
“chalcocite” Chalcocite is a copper sulphide mineral with the formula Cu2S and is an important copper ore mineral. It is opaque and dark-gray to black with a metallic luster.
“chalcopyrite” Chalcopyrite is a copper sulphide mineral with formula CuFeS2. It has a brassy to golden yellow colour.
“channel sample” Samples collected across a mineralised rock exposure. The channel is typically orientated such that samples are collected perpendicular to the mineralised structure, if possible.
“chargeability” Chargeability is a physical property related to conductivity. Chargeability is used to characterise the formation and strength of the induced polarisation within a rock, under the influence of an electric field, suggesting sulphide mineralisation at depth.
"CIM" The reporting standard adopted for the reporting of the Mineral Resources is that defined by the terms and definitions given in the terminology, definitions and guidelines given in the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Standards on Mineral resources and Mineral Reserves (December 2005) as required by NI 43-101. The CIM Code is an internationally recognised reporting code as defined by the Combined Reserves International Reporting Standards Committee.
“covellite” Covellite is a copper sulphide mineral with the formula CuS. This indigo blue mineral is ubiquitous in some copper ores.
“diamond drilling” A drilling method in which penetration is achieved through abrasive cutting by rotation of a diamond encrusted drill bit. This drilling method enables collection of tubes of intact rock (core) and when successful gives the best possible quality samples for description, sampling and analysis of an ore body or mineralised structure.
“digenite” Digenite is a copper sulfide mineral with formula Cu9S5. Digenite is a black to dark blue opaque mineral.
“dip” A line directed down the steepest axis of a planar structure including a planar ore body or zone of mineralisation. The dip has a measurable direction and inclination from horizontal.
“galena” Galena is the natural mineral form of lead (II) sulphide, with formula PbS. It is the most important ore of lead and an important source of silver.  It has a silver colour.
“grab sample” are samples of rock material collected from a small area, often just a few pieces or even a single piece of rock “grabbed” from a face, dump or outcrop or roughly 2-5kg. These are common types of rock samples collected when conducting mineral exploration. The sample usually consists of material that is taken to be representative of a specific type of rock or mineralisation. 
“grade” The proportion of a mineral within a rock or other material. For copper mineralisation this is usually reported as % of copper per tonne of rock (g/t).
"g/t" grams per tonne; equivalent to parts per million ('ppm')
“hematite” Hematite is the mineral form of iron(III) oxide (Fe2O3), one of several iron oxides.  Magnetite alteration is also typically associate with porphyry copper systems, at or close to the central core.
“hypogene” Hypogene ore processes occur deep below the earth's surface, and form deposits of primary minerals, such as chalcopyrite and bornite.  
"Indicated Resource" An “Indicated Mineral Resource” is that part of a Mineral Resource for which quantity, grade or quality, densities, shape and physical characteristics, can be estimated with a level of confidence sufficient to allow the appropriate application of technical and economic parameters, to support mine planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that are spaced closely enough for geological and grade continuity to be reasonably assumed.
"Inferred Resource" An “Inferred Mineral Resource” is that part of a Mineral Resource for which quantity and grade or quality can be estimated on the basis of geological evidence and limited sampling and reasonably assumed, but not verified, geological and grade continuity. The estimate is based on limited information and sampling gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes.
“Induced Polarisation Geophysics” Induced polarisation (IP) is a geophysical survey used to identify the electrical chargeability of subsurface materials, such as sulphides. The survey involves an electric current that is transmitted into the subsurface through two electrodes, and voltage is monitored through two other electrodes.
“intercept” Refers to a sample or sequence of samples taken across the entire width or an ore body or mineralised zone. The intercept is described by the entire thickness and the average grade of mineralisation.
"lbs" Pounds (measure of weight)
“Mlbs” Million pounds (measure of weight)
“magnetite” Magnetite is main iron ore mineral, with chemical formula Fe3O4. Magnetite is ferromagnetic, and it is attracted to a magnet and can be magnetized to become a permanent magnet itself.
“massive” In a geological sense, refers to a zone of mineralisation that is dominated by sulphide minerals.  The sulphide-mineral-rich material can occur in centimetre-scale, metre-scale or in tens of metres wide veins, lenses or sheet-like bodies containing sphalerite, galena, and / or chalcopyrite etc.
"Measured Resource" A “Measured Mineral Resource” is that part of a Mineral Resource for which quantity, grade or quality, densities, shape, and physical characteristics are so well established that they can be estimated with confidence sufficient to allow the appropriate application of technical and economic parameters, to support production planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration, sampling and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that are spaced closely enough to confirm both geological and grade continuity.
"Mineral Resource" A “Mineral Resource” is a concentration or occurrence of diamonds, natural solid inorganic material, or natural solid fossilised organic material including base and precious metals, coal, and industrial minerals in or on the Earth’s crust in such form and quantity and of such a grade or quality that it has reasonable prospects for economic extraction. The location, quantity, grade, geological characteristics and continuity of a Mineral Resource are known, estimated or interpreted from specific geological evidence and knowledge.
“mineralisation” In geology, mineralisation is the deposition of economically important metals (copper, gold, lead, zin etc) that in some cases can be in sufficient quantity to form mineral ore bodies.  
“open pit mining” A method of extracting minerals from the earth by excavating downwards from the surface such that the ore is extracted in the open air (as opposed to underground mining).
“outcrop” A section of a rock formation or mineral vein that appears at the surface of the earth.  Geologists take direct observations and samples from outcrops, used in geologic analysis and creating geologic maps. In situ (in place) measurements are critical for proper analysis of the geology and mineralisation of the area under investigation. 
“polymetallic” three or more metals that may occur in magmatic, volcanogenic, or hydrothermal environments; common base and precious metals include copper, lead, zinc, silver and gold. 
“polymict”  A geology term, often applied to breccias or conglomerates, which identifies the composition as consisting of fragments of several different rock types. 
“porphyry” Porphyry copper deposits are copper +- gold +- molybdenum orebodies that are formed from hydrothermal fluids that originate from a voluminous magma chamber below the deposit itself. 
“Preliminary Economic Assessment” NI 43-101 defines a PEA as “a study, other than a pre-feasibility study or feasibility study, which includes an economic analysis of the potential viability of mineral resources”.
“sediments” Sedimentary rocks formed by the accumulation of sediments. There are three types, Clastic, Chemical and Organic sedimentary rocks. 
“sequential assays” Sequential copper analysis is a technique to semi-quantitatively define the zonations associated with some copper deposits. The method is based on the partial dissolution behaviour displayed by the prevalent copper minerals to solutions containing sulphuric acid and sodium cyanide. Results from sequential analyses can theoretically determine the amounts of leachable oxide minerals, leachable secondary sulphide minerals, and primary copper minerals, respectively.
“sphalerite” Sphalerite is a zinc sulphide in crystalline form but almost always contains variable iron, with formula (Zn,Fe)S. It can have a yellowish to honey brown or black colour.
“supergene” Supergene ore processes occur near surface, and form deposits of secondary minerals, such as malachite, azurite, chalcocite, covellite, digenite, etc.  
“surface rock chip samples” Rock chip samples approximately 2kg in size that are typically collected from surface outcrops exposed along rivers and mountain ridgelines.
“veins” A vein is a sheet-like or anastomosing fracture that has been infilled with mineral ore (chalcopyrite, covellite etc) or mineral gangue (quartz, calcite etc) material, within a rock. Veins form when minerals carried by an aqueous solution within the rock mass are deposited through precipitation and infill or coat the fracture faces.
“volcanics” Volcanic rock such as andesite or basalt that is formed from magma erupted from a volcano, or hot clastic material that erupts from a volcano and is deposited as volcaniclastic or pyroclastics.