Name of the Project
Santo Tomas porphyry copper project.

Location
Sinaloa State, Mexico.

Project Owner/s
Oroco Resource Corporation.

Project Description
A revised preliminary economic assessment (PEA) and updated mineral resource estimate for the North Zone and South Zone of the Santo Tomas project have proposed a staged openpit mine and processing plant achieving 60 000 t/d in Year 1 and expanding to 120 000 t/d in Year 8 over a 22.6-year life-of-mine (LoM).

The PEA estimates total mineralised material mined at 825.5-million tonnes.

Total LoM payable copper production is estimated at 4.77-million pounds.

The proposed mining operation will use a conventional openpit truck-and-shovel operation with 10 m bench intervals. Haul trucks will transport mineralised material to the crushing plant and long-term stockpile facilities, and waste to the waste-rock storage facilities.

The mining sequence consists of 20 phases (ten in the north pit and ten in the south pit), which vary in minimum mining width according to the type of equipment to be used. 

Early years will focus on mining the north pit. Larger equipment will be used once the south pit has opened to wider benches. 

Mine haul trucks will transport plant feed material to the dump pockets at the semimobile primary crushing station, which directly feeds into a large gyratory crusher.

From the primary crusher, plant feed material will be conveyed through a tunnel to a live stockpile ahead of a processing plant containing a secondary cone and tertiary high-pressure grinding roll crushing circuit. 

Tertiary crushed product will feed into two twin ball mills in closed circuit, with cyclones to produce flotation feed at 80% minus 
150 µm. 

The flotation circuit will produce a bulk rougher concentrate that is subsequently reground to 23 µm P80 before cleaner flotation stages to produce a bulk copper/molybdenum concentrate.

The bulk cleaner concentrate advances to copper/molybdenum separation to recover a molybdenum concentrate. Gold and silver will progress to the copper concentrate. Copper and molybdenum concentrates are dewatered before shipment in sealed containers to a concentrate storage facility at the Port of Topolobampo for shipment to overseas smelters. 

Project expansion (Phase 2) starts in Year 8 of operation.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
The PEA estimates a net present value of $2.64-billion, at an 8% discount rate, and an internal rate of return of 30.3%, with a payback of 2.9 years.

Capital Expenditure
Initial capital costs are estimated at $1.1-billion.

Planned Start/End Date
Not stated.

Latest Developments
Not stated.

Key Contracts, Suppliers and Consultants
Ausenco Engineering USA South Inc (PEA); and SRK Consulting (US) Inc and SRK Consulting (Canada) Inc (updated mineral resource estimate and geologic model).

Contact Details for Project Information
Oroco Resource Corporation, tel +1 604 688 6200 or email info@orocoresourcecorp.com.