This Preliminary Economic Assessment reports a proposed processing route combining flotation concentrate treatment with heap leaching of oxide material for the Fremont Gold Project in Mariposa County, California.
Report context
The Fremont Gold Project is located in Mariposa County, central California, USA, at UTM NAD83 Zone 10N coordinates 754,360 m E and 4,164,460 m N, longitude 120° 07' W and latitude 37° 36' N. The technical report, with an effective date of February 15, 2023, and signing date of March 31, 2023, was prepared for Stratabound Minerals Corp. as a NI 43-101 and 43-101F1 Preliminary Economic Assessment.
Processing route
Previous Operations
Historical production from the Fremont Gold Project area indicates that gold was recovered through earlier mining operations. The report notes past production as part of the property history, but does not provide specific metallurgical performance data from those historical operations within the processing sections available for this summary.
Metallurgical Testwork
A testwork program was conducted to evaluate the metallurgical characteristics of the mineralization. Scoping test work was performed as an initial phase of investigation. Historical test work examined multiple processing options in detail, including grinding studies, flotation and concentrate dewatering tests, gravity concentration, treatment of carbon removal products, roasting and calcine leaching, sulphur dioxide absorption capacity of flotation tailings, bioleaching, and heap leaching of oxide mineralized material. In 2014, additional test work included comminution testing, rougher flotation kinetic tests, rougher-cleaner circuit flotation tests, gravity concentration, combined gravity separation and flotation tests, bottle roll direct cyanide leach tests, and bottle roll carbon-in-leach (CIL) tests.
Proposed Recovery Methods
The proposed processing route consists of two main components: a flotation concentrator and a heap leach operation. The flotation concentrator includes crushing, a crushed stockpile and reclamation system, grinding and gravity separation, flotation and regrind, concentrate dewatering, tailings management, and paste backfill. The heap leach component includes screening and crushing, agglomeration, conveying and stacking, a leach pad, leaching systems, a solution collection system, and adsorption.
Process design criteria are defined separately for the flotation concentrator and the heap leach. Reagents specified for the flotation concentrator include potassium amyl xanthate (PAX), Aero 208, and methyl isobutyl carbinol (MIBC). Reagents for the heap leach include sodium cyanide and cement.
Key reported parameters
The following table summarizes the key processing parameters reported, distinguishing between design parameters, historical testwork, and actual data where specified.
| Parameter | Value | Basis | Notes |
|---|---|---|---|
| Comminution testing | Conducted | 2014 testwork | Historical test program |
| Rougher flotation kinetic tests | Conducted | 2014 testwork | Historical test program |
| Rougher-cleaner circuit flotation tests | Conducted | 2014 testwork | Historical test program |
| Gravity concentration testing | Conducted | 2014 testwork | Historical test program |
| Combined gravity separation and flotation testing | Conducted | 2014 testwork | Historical test program |
| Bottle roll direct cyanide leach tests | Conducted | 2014 testwork | Historical test program |
| Bottle roll CIL tests | Conducted | 2014 testwork | Historical test program |
| Heap leaching of oxide material | Tested | Historical testwork | Scoping-level |
| Roasting and calcine leaching | Tested | Historical testwork | Scoping-level |
| Bioleaching | Tested | Historical testwork | Scoping-level |
| PAX reagent | Specified | Design | Flotation collector |
| Aero 208 reagent | Specified | Design | Flotation collector |
| MIBC reagent | Specified | Design | Frother |
| Sodium cyanide | Specified | Design | Heap leach reagent |
| Cement | Specified | Design | Heap leach reagent |
Project website: https://lode-gold.com/article/stratabound-minerals-the-next-high-growth-north-american-gold-producer/
Technical qualifications
The report is a Preliminary Economic Assessment (PEA) and therefore does not represent a feasibility study. The processing and recovery methods described are proposed designs based on historical testwork and 2014 testwork programs. No actual operating performance data from the proposed processing circuits is reported, as the project is at the PEA stage. The mineral processing and metallurgical testing sections rely on historical testwork that was conducted for scoping and evaluation purposes, not for final process design. Capital and operating cost estimates, economic analysis, and other financial parameters are based on this PEA level of study.
Source: Preliminary Economic Assessment of the Fremont Gold Project, Mariposa County, Central California, USA, NI 43-101 & 43-101F1 Technical Report, Stratabound Minerals Corp., Effective Date February 15, 2023, Sections 13.0 Mineral Processing and Metallurgical Testing, 17.0 Recovery Methods.
