The 2022 technical report presents a preliminary economic assessment for the Magistral Project, a gold-silver tailings retreatment project in Durango, Mexico, based on proposed design, historical operating data, and recent metallurgical testwork.
Report context
This NI 43-101 technical report, with an effective date of 12 December 2021 and prepared for Tarachi Gold Corp., describes the Magistral Project located at Magistral de Oro, Durango, Mexico. The report was prepared by Ausenco Engineering Canada Inc. and AGP Mining Consultants Inc. The project involves the retreatment of historic tailings material. The report incorporates results from metallurgical testwork programs conducted in 2012, 2016, and 2021, as well as historical operational data from previous processing at the site.
Processing route
Proposed processing design
The recovery methods section of the report outlines a proposed process flowsheet for treating the historic tailings material. The process plant design includes grinding, cyanide leaching, counter-current decantation (CCD), sulfidation-acidification-recycling-thickening (SART), Merrill-Crowe precipitation and refinery, and cyanide destruction. Final tailings slurry transport is also included in the proposed design.
The proposed grinding circuit is designed to prepare the feed material for leaching. The cyanide leaching circuit follows grinding. The CCD circuit is designed for solid-liquid separation. The SART circuit is specified for treatment of the pregnant solution. Merrill-Crowe precipitation and a refinery are included for gold and silver recovery. Cyanide destruction is incorporated in the flowsheet before final tailings disposal.
Reagent handling and storage facilities are included in the proposed plant design. Plant services comprise fresh water and process water systems, an oxygen plant, electrical power supply, and sampling and quality control facilities.
Historical operating data
The report documents historical mining and processing activity at the Magistral property dating back to the early 20th century. A carbon-in-leach (CIL) plant was constructed and operated on the property by Proyecto Magistral SRLCV and Promociones Metrópolis between 2011 and 2016. This CIL plant provides historical operating data relevant to the project. Additional historical processing was conducted by Compañía Magistral del Oro between 1950 and 1960, and by Minera Magistral del Oro and Consolidated Nevada Goldfields between 1992 and 1996. Altos Hornos de Mexico S.A. (Real del Monte y Pachuco) operated on the property from 1990 to 2018, and MINOSA operated from 2014 to 2018. Real del Monte y Pachuca conducted mining and exploration in the 1920s through 1940 and again in 1985 and 2004.
Metallurgical testwork
Three separate metallurgical testwork programs are referenced in the report. The KCA testwork program was conducted in 2012. The Metsolve testwork program was completed in 2016. The Base Metallurgical Laboratories testwork program was conducted in 2021. These testwork programs provide the basis for recovery estimates and process design parameters.
Recovery estimates for gold and silver are derived from these metallurgical testwork programs. Deleterious elements were also evaluated as part of the testwork programs.
Key reported parameters
| Parameter | Value | Unit | Basis |
|---|---|---|---|
| Gold recovery estimate | Reported from testwork | % | Metallurgical testwork |
| Silver recovery estimate | Reported from testwork | % | Metallurgical testwork |
| Grinding circuit design | Included in flowsheet | , | Proposed design |
| Cyanide leaching circuit design | Included in flowsheet | , | Proposed design |
| CCD circuit design | Included in flowsheet | , | Proposed design |
| SART circuit design | Included in flowsheet | , | Proposed design |
| Merrill-Crowe precipitation design | Included in flowsheet | , | Proposed design |
| Cyanide destruction design | Included in flowsheet | , | Proposed design |
| Historical CIL plant operation | 2011–2016 | , | Historical operating data |
Project website: https://www.juniorminingnetwork.com/junior-miner-news/press-releases/2810-cse/trg/135167-tarachi-gold-announces-sale-of-magistral-project.html
Technical qualifications
The qualified persons responsible for the processing and recovery methods sections of the report have not visited the Magistral Project site. The report was prepared as a preliminary economic assessment and is based on information available at the time of preparation, data supplied by outside sources, and the assumptions, conditions, and qualifications set forth in the report. The quality of information, conclusions, and estimates is consistent with the level of effort involved in the services provided. This report is intended for use by Tarachi Gold Corp., subject to terms and conditions of its contracts with the report authors.
*Source: Magistral Project NI 43-101 Technical Report on Preliminary Economic Assessment, Magistral del Oro, Mexico, effective date 12 December 2021, Sections 13 and 17.*
