Location and Infrastructure

The Toroparu Project is situated in the Mazaruni Mining District in the Upper Puruni River Region of western Guyana and contains one of the largest undeveloped gold/copper projects in the Americas.

The Toroparu project is located near other significant gold deposits within the Guiana Shield. Aris Mining’s 100% controlled Upper Puruni Concession contains 53,283 hectares of mineral leases.

Toroparu can be accessed from Georgetown by road and ferry, a journey that takes between 12 to 16 hours in the dry season from August to May. The project is also accessible by air via charter flight from Georgetown arriving at a landing strip on site. The existing facilities include an exploration camp, airstrip, and site roads. During construction and mine operations, transport of equipment, materials, and supplies will be by barge and truck from Georgetown to a newly constructed port and then overland to the project. Power will be generated on site and water will be sourced from impounding a portion of the Wynamu River, surface reservoirs, and rainwater harvesting systems.

Mining and Processing

Mining will take place by conventional truck and shovel open pit methods in five separate pits, followed by concurrent underground mining in year nine using longitudinal open stoping with cemented paste backfill and truck haulage to surface.

Two processing plants are planned to treat the various ore types. The initial 7,000 tpd gold plant will comprise crushing, semi-autogenous grinding with a gravity gold circuit, intensive cyanidation of the gravity concentrate, leaching of the fine slurry in a carbon-in-leach process, and recovery of loaded carbon and elution to recover gold and silver, electrowinning, and smelting the final gold-silver doré product. The plant will be expanded with the addition of a 7,000 tpd flotation plant in year six, comprising crushing, ball milling with a gravity gold circuit, intensive cyanidation of the gravity concentrate, a flotation circuit for the recovery of a gold-silver-copper concentrate, and dewatering and filtration of the concentrate product. Tailings will be managed in a tailings storage facility.

Geology and Mineralization

The Toroparu deposit comprises multiple parallel steeply dipping structures in a 2.7 kilometre long, 40 metre to 200 metre wide, and over 400 metre deep corridor that is open at depth. Gold and copper mineralization is controlled by fracture veinlet stockworks with two sets of cross cutting, higher grade structures, hosted in intrusive mafic volcanics in contact with quartz diorite intrusives, overlain by 10 metre to 35 metre thick gradational saprolite.

The Sona Hill deposit is located 3.2 kilometres southeast of Toroparu, with gold hosted in sub-horizontal, shallow dipping structures with two sets of cross cutting high-grade gold structures. The mineralization is hosted in intrusive lithologies, porphyry, granodiorite, and quartz diorite.

Preliminary Economic Assessment Highlights

A 2021 preliminary economic assessment (PEA) on the Toroparu Project shows base case economics with a post-tax NPV5% of $794 million using metal prices of US$1,500 per ounce for gold sold to market and $400 per ounce for gold sold to Wheaton Precious Metals under a precious metals purchase agreement. The PEA outlines a 24-year mine life from open pit and underground mining operations, with total gold production of 5.4 million ounces at AISC of $916 per ounce. Estimated initial capital costs are US$355 million, including pre-stripping costs, construction of site facilities, equipment purchases, and the construction of the leaching plant, and $US281 million of expansion capital to construct the flotation circuit in years four and five. Sustaining capital is estimated at US$662 million.

The Preliminary Economic Assessment is preliminary in nature and is based on numerous assumptions and includes inferred mineral resources. The inferred mineral resources are considered too speculative geologically to have economic considerations applied to them that would enable them to be categorized as mineral reserves and there is no certainty that the Preliminary Economic Assessment will be realized.

The updated application for the mining license was submitted in early 2022 and expected to be finalized by the fourth quarter of 2022.


@ 1.42 g/t

M&I gold Mineral Resources

225 koz

per year

Gold production (LOM average)

1.2 Moz

@ 2.74 g/t

Inferred gold Mineral Resources



AISC (LOM average)

24 year


Mine Life



Development capex

5.4 Moz


Total LOM gold production



Post-tax NPV1 (5%)

Notes:  1. Assumes US$1,500/oz gold price.