Australia

Endeavor Mine

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Overview

Mine TypeUnderground
StageRestarting
Commodities
  • Silver
  • Zinc
  • Lead
Mining Method
  • Sub-level open stoping (SLOS)
  • Cut & Fill
  • Hydraulic mining
  • Longhole open stoping
  • Cemented paste backfill
  • Cemented rockfill
  • Unconsolidated rockfill
Production Start... Lock
Mine Life10 years (as of Jan 1, 2023)
ShapshotThe Endeavor Project is endowed with extensive infrastructure, in good condition, ready to be utilised once mining recommences. Surface infrastructure includes a 1.2Mtpa processing plant, rail loading facility, raw water and electricity connections to local grids, workshops, partly stocked stores warehouse, offices, and a laboratory. Underground infrastructure includes a tower mounted friction winder for hauling ore to the surface, a truck haulage decline from surface to 9135mRL, underground crushing station, workshops, refuelling station, dewatering pump station, refuge chambers and reticulated water and air.

The Project Restart Study is based on a mine plan and optimised mining schedule that includes initial mining from three zones in the underground mine as well as the later retreatment of high-grade Sector 1 tailings that were produced during the early years. Mining of underground ore extends from Years 1 to 6 and re-treatment of Sector 1 tailings commences in Year 5.

Owners

SourceSource
CompanyInterestOwnership
CBH Resources Limited 100 % Indirect
The mine is owned by Cobar Operations Pty Ltd (COPL), operated by Endeavor Operations Pty Ltd (EOPL), with housing infrastructure managed by Cobar Infrastructure Pty Ltd (CIPL). The three companies are currently wholly owned subsidiaries of CBH Resources Ltd (CBH). CBH is owned by Toho Zinc, a Japanese listed company.

Polymetals, through its 100% owned subsidiary company Cobar Metals Pty Ltd, has entered into a legally binding arrangement to acquire 100% of the Endeavor mine and associated assets by acquiring COPL, EOPL and CIPL from CBH. In order to complete the acquisition, Cobar Metals will be required to secure the release and replacement of the Environmental Rehabilitation Bond on or before 30 April 2024.

Contractors

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Deposit type

  • Tailings
  • Vein / narrow vein

Summary:

The Endeavor zinc-lead-silver mine (initially known as the Elura) is located 43km NNW of Cobar. The mine contains two styles of mineralisation: above about 900m depth an irregular sub-vertical sheet is hosted by a turbidite sequence and broadly coincides with an anticline axial plane; at the bottom of this sheet mineralisation bifurcates into grossly concordant zones.

Six main ore types have been identified within the Endeavor Mine orebody:
• Pyritic mineralisation (PY),
• Pyrrhotitic mineralisation (PO),
• Silicious pyrrhotitic ore (SIPO),
• Silicious Pyritic ore (SIPY),
• Vein ore, and
• Mineralised altered CSA siltstone (MINA).

Mineralisation at the Elura deposit is hosted by a fine grained turbidite sequence of the Cobar Basin and comprises multiple sub-vertical elliptical shaped pipe-like pods that occur within the axial plane of an anticline and are surrounded by an envelope of sulphide stringer mineralisation, in turn surrounded by an envelope of siderite alteration extending for tens of metres away from the sulphide mineralisation. Around 150m below the base of the main mineralised pods/lodes, mineralisation is hosted within the western limb of a folded limestone unit, occurring in veins and fractures. A zone of supergene enrichment occurs at the top of the Main Lode. Recent reviews favour a syngenetic formation model of an original stratiform deposit that was later emplaced by tectonic force into a favourable structural site during deformation.

The Elura deposit is hosted by a limestone breccia overlain by a turbidite sequence of interbedded shale and sandstone/siltstone. The carbonate rocks have been interpreted as belonging to the Brookong Formation of the Kopyje Group and the turbidites are thought to be lithologically equivalent of the CSA Siltstone.

The main orebody is massive sulphide hosted by the fine grained turbidite sequence and comprises multiple sub-vertical elliptical shaped pipe-like pods with an envelope of sulphide stringer mineralisation, in turn surrounded by an envelope of siderite alteration extending for tens of metres away from the sulphide mineralisation. Above about 900m depth, the sulphide stringer mineralisation occurs as a large continuous 15 - 120m wide sheet within the axial plane of an anticline and extends over a strike length of at least 800m. Below 900m depth the stringer zone breaks up and occurs as grossly concordant zones paralleling the limbs of the anticline.

The orebody is generally divided up into the main lode, which consists of two elliptical pods that merge together around 10 000 m RL and the northern Pods which consist of five smaller crudely elliptical orebodies that trend towards the NNW and dip approximately 80° - 85° towards the west. The crusher pod, which is located on the eastern side of the main lode, is a small apophysis that merges into the Main Lode at the 9500 m RL.

Mineralisation in the orebody is complex. The primary lead and zinc bearing minerals from all orebodies processed are galena (~13 per cent wt) and sphalerite (~14 per cent wt). Pyrite and pyrrhotite (~60 - 70 per cent wt in total) are the main floatable gangue in the ore. Tetrahedrite is the major host of silver, apart from galena and chalcopyrite. The average grain size of galena and sphalerite are relatively very fine, ranging from 10 - 40 µm.

Tailings
Mineralised material in the tailings storage facility consists of clay to fine sand sized particles deposited in sub-horizontal layers from centrally located outflow sites. The particles contain remnant sulphides that were not captured during processing of the Endeavor Mine silver-zinc-lead ore. The primary lead and zinc bearing minerals from all orebodies processed are galena (~13%wt) and sphalerite (~14%wt). Pyrite and pyrrhotite (~60 to 70%wt in total) are the main floatable gangue in the ore. Tetrahedrite is the major host of silver, apart from galena and chalcopyrite.

The mine commenced operations in 1983 and tailings were pumped exclusively into Sector 1 from March 1983 until April 1989 (with the exception of tailings from concurrent Ag supergene mining which were pumped to a separate, smaller TSF southwest of the mine) when Sector 2 of the TSF was commissioned. No further tailings have been added to Sector 1 since 1989.

The northern portion of Sector 1 was rehabilitated in 1991 when the surface was re-contoured, covered with plastic, clay capped, and topsoil emplaced.

The TSF is a raised “turkey’s nest” type dam, with Sector 1 measuring approximately 550m by 850m and an average depth of around 7m.

Reserves

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Mining Methods

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Comminution

Crushers and Mills

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Processing

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Production

Reported 2017 production and financial results include operations through May 2017 in accordance with the terms of the sale agreement.

Production 2018 includes attributable silver oz. from the Endeavor silver stream that were produced, shipped and provisionally invoiced during June and July 2017, where the Metalla Royalty & Streaming Ltd. is entitled to the associated trade receivable amounts.
CommodityProductUnits2018201720162015LOM
Silver Payable metal koz 5021072486299,757
Silver Metal in lead concentrate koz 10,285
Zinc Payable metal M lbs 463
Zinc Metal in zinc concentrate M lbs 551
Zinc Concentrate kt 48499
Lead Payable metal M lbs 137
Lead Metal in lead concentrate M lbs 145
Lead Concentrate kt 27130

Operational metrics

Metrics
Annual ore mining rate 000000
Annual processing capacity 00
Annual processing rate 000000
Ore tonnes mined, LOM 000
Tonnes processed, LOM 000
Tonnes milled
* According to 2023 study.

Production Costs

CommodityUnitsAverage
Total cash costs (sold) Silver USD
Assumed price Lead USD 0000
Assumed price Zinc USD 0000
Assumed price Silver USD 00
* According to 2023 study / presentation.

Operating Costs

Currency2023
UG mining costs ($/t milled) AUD 86.6 *  
* According to 2023 study.

Project Costs

MetricsUnitsLOM Total
Pre-Production capital costs $M AUD  ......  Subscribe
Sustaining CapEx $M AUD  ......  Subscribe
Total CapEx $M AUD  ......  Subscribe
UG OpEx $M AUD  ......  Subscribe
Processing OpEx $M AUD 193.2
Refining and transportation $M AUD  ......  Subscribe
G&A costs $M AUD 86.7
Total OpEx $M AUD  ......  Subscribe
Royalty payments $M AUD  ......  Subscribe
Gross revenue (LOM) $M AUD  ......  Subscribe
EBITDA (LOM) $M AUD  ......  Subscribe
Pre-tax Cash Flow (LOM) $M AUD  ......  Subscribe
Pre-tax NPV @ 8% $M AUD  ......  Subscribe
After-tax NPV @ 8% $M AUD  ......  Subscribe
Pre-tax IRR, %  ......  Subscribe
After-tax IRR, %  ......  Subscribe
Pre-tax payback period, years  ......  Subscribe

Heavy Mobile Equipment

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Personnel

Mine Management

Source Source
Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Jan 26, 2024
....................... Subscription required ....................... Subscription required Subscription required Jan 26, 2024
....................... Subscription required ....................... Subscription required Subscription required Jan 26, 2024
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EmployeesTotal WorkforceYear
Subscription required 2023
Subscription required 2021
Subscription required 2020
Subscription required 2019
Subscription required 2018

Aerial view:

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