Sonoro Gold Corp. Reports Bottle Roll Tests of Cerro Caliche Mineralization Return Average Recoveries of 80.3% for Gold
9:00 AM ET, 03/03/2021
VANCOUVER, British Columbia, March 03, 2021 (GLOBE NEWSWIRE) -- Sonoro Gold Corp.(TSXV: SGO | OTCQB: SMOFF | FRA: 23SP) “Sonoro” or the “Company” is pleased to report the bottle roll results from the Company’s Cerro Caliche property in Sonora, Mexico. The samples tested were from four specific mineralized zones: Japoneses, Cuervos, El Colorado/Cabeza Blanca and Buena Suerte, and included associated composites. The testing was conducted at McClelland Laboratories, Inc. in Sparks, Nevada as part of a detailed scope of work consisting of 43 bottle roll tests over 96-hours at a coarse sizing of 80% - 1.7 mm feed size. Subsequent leach recoveries averaged 80.3% for gold and 27.2% for silver. Sodium cyanide consumption rates averaged 0.20 kg/t and lime addition averaged 2.1 kg/t for the bottle roll tests at varying feed grades. These recoveries are similar in all structures and domains while cyanide consumption, which averaged 0.2-0.3 kg/t, together with the amount of lime required for pH control (approximately 2 kg/t) are well within acceptable levels.
The leaching profile indicated a fast recovery over the 24-hours for gold, with a slower profile for silver as expected. Variability is as shown in the following graphs supplied by McClelland Laboratories for the specific zones and composites.
Photos accompanying this announcement are available at: https://www.globenewswire.com/NewsRoom/AttachmentNg/da6b5c99-9302-4323-9f8b-ef942c41e6b4https://www.globenewswire.com/NewsRoom/AttachmentNg/ff32ff19-dc0a-40d7-99b5-71d19fdfd815
The samples tested were from over 5,500 kilograms of mineralized material taken from ten 85-mm diameter PQ core holes which were drilled to depths ranging from 25 to 140 meters. The balance of the mineralized material is being used for the column leach tests at McClelland Laboratories.
Drilling at Cerro Caliche has shown that the mineralization throughout the various zones is oxidized to the full extent of all the drill holes. Bottle roll test results verify previous observations that mineralization characteristics of near-surface oxidized drill cuttings were similar to the deeper oxidized mineralization.
The map below shows the locations of the PQ core drill holes.
A map accompanying this announcement is available at https://www.globenewswire.com/NewsRoom/AttachmentNg/fc9a7785-ac22-4fc1-9f17-49f037559855
Sonoro’s Vice President Operations, Jorge Diaz, stated, “We are pleased with these results as it shows the mineralization is amenable to cyanide leaching and provides good recoverability at a coarse mesh bottle roll of 1.7mm. We are also encouraged by the fact that these bottle roll tests, which were conducted on various ore types and across various zones within the property, demonstrate similar positive metallurgical recoveries across the entire resource area.”
Sonoro’s President and CEO, Kenneth MacLeod, added, “The successful completion of these tests is an important
advancement of the Cerro Caliche project and will contribute towards the completion of the NI 43-101 P.E.A. that is expected to be released during Q3-2021. The results validate the projected 72% recovery rate used in the Company’s July 26, 2019 NI 43-101 Technical Report1 which provided the project’s initial mineral resource estimate.”
As previously planned, based on the bottle roll composites, the column test work has now commenced at McClelland Laboratories. The column testing consists of 17 columns on 9 mineralized zones and 8 composites on 2 crush sizes of 2-inch to 0.5-inch feed sizes. The Company expects these column tests to run for up to 90 days and will report the results as they become available.
Sonoro’s Chairman, John Darch, concluded, “The importance of this independent confirmation of the gold recoveries which now form the basis of our assessment of a 20,000 tpd heap leach mining operation cannot be understated as they are a critical milestone with regard to the project’s advancement. That these bottle roll test results are very much in line with management’s assumed recoveries speak volumes as to the acumen, professionalism and best-in-class practices employed by the Sonoro team.”
Quality Assurance/Quality Control (“QA/QC”) Measures and Analytical ProceduresThe PQ drill cores for metallurgical testing were drilled to normal industry standards, with the cores sequentially placed in 4-row plastic core boxes, then kept in secure storage and packed onto wooden pallets prior to shipping to McClelland Laboratories by DHL.
No QA/QC issues were noted with the results received from the laboratory. McClelland Laboratories, Inc. maintains accreditation with ISO/IEC Standard 17025:2017, for fields of testing that include the fire assay and solution analyses used for the current metallurgical testing program.
Geologic DescriptionCerro Caliche is located 45 kilometers east southeast of Magdalena de Kino in the Cucurpe-Sonora Mega-district of Sonora, Mexico. Multiple historic underground mines were developed in the concession including Cabeza Blanca, Los Cuervos, Japoneses, Las Abejas, Boluditos, El Colorado, Veta de Oro and Espanola. Mineralization types of the Cucurpe-Sonora Mega-district include variants of epithermal low sulfidation veins and related mineralized dikes and associated volcanic domes. Local altered felsic dikes cut the mineralized meta-sedimentary rock units and may be associated with mineralization both in the dikes and meta-sedimentary rocks.
Host rocks include Jurassic-Cretaceous meta-sedimentary rock units including argillite, shale, quartzite, limestone, quartz pebble conglomerate and andesite. Younger intrusive rock consisting of medium coarse-grained granodiorite-granite is present in the westerly parts of the concessions near the historic Cabeza Blanca Mine. It is apparent that veining cuts and pervasively alters the intrusive stock. Rhyolite occurs in irregular bodies distributed in higher elevations in the northerly part of the concession, including the Rincon area, where it occurs as flows, sills, dikes and rhyolite domes. Part of the rhyolite is mineralized and appears to be related to epithermal gold mineralization throughout the property.
Qualified Person StatementStephen Kenwood, P.Geo., a Director of Sonoro, is a Qualified Person within the context of National Instrument 43-101 (NI 43-101) and has read and approved this news release. Readers are cautioned that the presence of mineralization on historic mines adjacent to or on Cerro Caliche is not necessarily indicative of gold mineralization in the concessions held by the Company.