Ghana

Chirano Mine

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Overview

Mine TypeOpen Pit & Underground
StatusActive
Commodities
  • Gold
Mining Method
  • Truck & Shovel / Loader
  • Sub-level caving
  • Longhole open stoping
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Mine Life... Lock
SnapshotThe change in fiscal year by Asante Gold brings about a profound implication. The data for the full year 2022, previously reported under Kinross's calendar, now aligns with Asante Gold's fiscal year, categorizing it as the year 2023 in their financial statements. This realignment ensures that the financial data accurately represents Asante Gold's operational performance during its tenure as the owner of Chirano Mine.

Chirano consists of a multi-deposit complex of 11 mineralized deposits that have been historically mined from both open pit and underground operations since 2005. It had been under Kinross management from 2010 to 2022. The Mine includes open pit operations at the Mamnao (North, Central, South) and six underground operations on the Akwaaba, Suraw, Akoti, Paboase, Tano and Obra Deposits. The Chirano Gold Mine is fully permitted.

Owners

SourceSource
CompanyInterestOwnership
Asante Gold Corp. 90 % Indirect
Chirano Gold Mines Ltd. (operator) 100 % Direct
On August 10, 2022, Asante Gold Corp. closed the acquisition of all of the issued and outstanding shares in the capital of Red Back Mining Pty Ltd, which indirectly holds a 90% interest in the Chirano Gold Mine (“Chirano”) pursuant to a share purchase and sale agreement dated April 24, 2022, as amended, (the “Purchase Agreement”) among the Company, KG Africa B.V. (the “Vendor”), an indirect subsidiary of Kinross Gold Corporation (“Kinross”), and Kinross (the “Chirano Acquisition”). The Ghanaian government will continue to retain a 10% carried interest in Chirano.

Contractors

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Deposit type

  • Breccia pipe / Stockwork
  • Vein / narrow vein

Summary:

In Ghana, the Paleoproterozoic Birimian terrains consist of five linear northeast-trending volcanic belts with intervening sedimentary basins. The volcanic belts have been folded by multiple deformation events and are generally 15-40 km wide and extend for several hundred kilometres laterally. The Kumasi Basin is 90 km wide and lies between the Ashanti Belt to the south-east and the Sefwi Belt to the north-west. The combined Sefwi and Ashanti volcanic belts and intervening Kumasi Basin host most of the gold endowment in Ghana. Other world class deposits within the Belt include Ahafo (20Moz, Newmont) and Bibiani (2.3Moz, Asante).

On a regional scale, the Chirano Gold Mine is located on the eastern limb of the West African Precambrian Shield which is a cratonised complex of Archaean basement. Most gold deposits in Ghana are located in or adjacent to the Ashanti Gold Belt, the Bibiani-Sefwi Belt and the Asankrangwa Belt.

The Chirano mines and associated mineralized deposits lie within the Proterozoic terrain of southwest Ghana along a major structure separating the Sefwi Belt to the west from the Kumasi Basin to the east known as the Bibiani Shear Zone ("BSZ"). The belt and basin architecture comprises rocks of Birimian age, with the belts being dominated by mafic volcanics and the basins typified by fine-grained, deep marine sediments. Both are intruded by granites. The Chirano deposits lie close to a splay off the BSZ known as the Chirano Shear Zone ("CSZ"). The deposits occur at regular intervals along a mineralized zone over 11 km long. The mineralized zone is characterized by foliation, veining and brecciation, and is interpreted as a splay fault of the CSZ with mineralization occurring within 200m to the west of the CSZ.

The deposits are hosted by fractured and altered mafic volcanics and granite and include stacked arrays of parallel veinlets, veinlet stockworks and mineralized cataclasites. The geometry and shape of the deposits range from tabular (Obra), or pipe-like (Tano) to multiple parallel lodes (Paboase). The mineralized zone thickness ranges from a few metres to over 70m. Most deposits dip very steeply towards the west or southwest and plunge steeply. Generally, the tenor of mineralization is related to intensity of hydrothermal alteration (silica, ankerite, albite, sericite, pyrite), veining and brecciation. The gold is finegrained and is associated with 1% - 5% pyrite.

The deposits occur close to a major fault, the Chirano Shear Zone (“CSZ”), and is considered likely that any new deposits found will also be closely associated with faulting. Individual deposits are often closely associated with small dextral jogs in the host structure. Although the currently known gold deposits are in granite, there are also strong gold anomalies in Birimian metasediments elsewhere within the mine area, which require concerted follow-up exploration. The Bibiani Shear Zone (“BSZ”) is the fault contact between the Tarkwaian sediments and the Kumasi Basin sediments.

The deposits range in strike length from 150m to 700m, and range in thickness from a few metres to over 70m. They vary from rather tabular (Obra, Sariehu, Suraw) to more pipe-like (Tano and Akoti North) morphologies. The longer, the more tabular bodies generally comprise at least two shorter lenticular shoots, such as the Obra main and north lenses. These lenses may be separated by a small dextral jog such as those at Obra and Sariehu. Within the Paboase Bulge there are several parallel lodes, whereas elsewhere along the mineralized horizon there is commonly only a single zone is evident.

Most of the deposits dip steeply to the west, however shallow west, vertical and steep east dips occur locally. The mineralization plunges either directly down dip or steeply northwards. The mineralization demonstrates excellent continuity, there being no known gaps due to oblique faults or dykes.

Unusually flat dips have been noted in short sections of the lode horizon at Mamnao Central (39,850 N to 39,975 N), Obra South (36,850 N to 36,950 N), Sariehu (38,400 N), and Akoti South (34,635 N), however these areas do not demonstrate any spatial relationship with thicker or higher-grade mineralized intervals.

The Akwaaba deposit is hosted in quartz dolerite and mineralisation is associated with fractionated quartz (feldspar) porphyry. The mineralisation is comprised of both a main and foot wall lode and a hanging wall zone. The Paboase mineral deposit lies in the centre of the Chirano mineralised zone and is related to a sinistral jog in the Chirano shear. It is the deepest part of the mineralised trend to the 1400mrl. Both deposits remain open in depth.

Obra deposit is developed almost exclusively in tonalitic rocks and is unique in that it has a very large shear on its western margin (the Obra Shear) as well as on the eastern side (the Chirano Shear) and as such is less asymmetric. It is also unusually wide and low grade probably because the entire volume of rock between the two shears has been fractured and mineralised. Mineralisation is associated with overprinting of breccia fabric and exhibits strong carbonate-silica-pyrite alteration. Obra currently has both open pit and underground reserves reported.

Underground operations at Tano are the depth extension of a previously mined open pit. The workings are currently accessed via an underground drift from Paboase in addition toits own portal that is near completion.

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

On August 10, 2022, the Kinross announced that it had completed the sale of its 90% interest in the Chirano mine in Ghana to Asante Gold Corporation. Data was taken and calculated from two companies (Kinross and Asante).
CommodityUnits202420232021202020192018201720162015
Gold Equivalent oz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe201,296226,699246,027211,954256,098
All production numbers are expressed as metal in doré. ^ Guidance / Forecast.

Operational metrics

Metrics202420232021202020192018201720162015
Ore tonnes mined  ....  Subscribe  ....  Subscribe  ....  Subscribe2,569 kt2,013 kt2,410 kt2,722 kt3,046 kt
Annual ore mining rate  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
Annual milling capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe3.5 Mt3.5 Mt3.5 Mt3.5 Mt
Tonnes processed  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe3,457 kt3,506 kt3,438 kt3,458 kt3,492 kt
^ Guidance / Forecast.

Production Costs

Commodity202320212020201920182017
Cash costs (sold) Gold Equivalent  ....  Subscribe  ....  Subscribe 940 / oz  USD 768 / oz  USD 797 / oz  USD
All-in sustaining costs (sold) Gold Equivalent  ....  Subscribe

Financials

Units202320212020201920182017
Sustaining costs M CAD  ....  Subscribe
Capital expenditures M  ....  Subscribe  ....  Subscribe 18.8  USD 24  USD 46.6  USD
Revenue M  ....  Subscribe  ....  Subscribe  ....  Subscribe 281.6  USD 286  USD 317.6  USD
Operating Income M  ....  Subscribe  ....  Subscribe -7.8  USD -6.2  USD -27.5  USD
Gross profit M  ....  Subscribe  ....  Subscribe -0.7  USD -10.5  USD -21.1  USD

Heavy Mobile Equipment

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Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Sep 7, 2023
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....................... Subscription required ....................... Subscription required Subscription required Sep 7, 2023
....................... Subscription required ....................... Subscription required Subscription required Sep 7, 2023

EmployeesContractorsYear
...... Subscription required ...... Subscription required 2021
...... Subscription required ...... Subscription required 2020
...... Subscription required ...... Subscription required 2019
...... Subscription required ...... Subscription required 2018
...... Subscription required ...... Subscription required 2017
...... Subscription required ...... Subscription required 2016

Aerial view:

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