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Summa Silver Corp
Symbol SSVR
Shares Issued 91,324,869
Close 2023-08-16 C$ 0.465
Market Cap C$ 42,466,064
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Summa Silver's Hughes met tests recover up to 96.7% Ag

2023-08-16 11:55 ET - News Release

Mr. Galen McNamara reports


Summa Silver Corp. has released silver and gold recovery results from initial scoping-level metallurgical test work from its Hughes project, near Tonopah, Nev. Results demonstrate strong recoveries of silver and gold from the Murray and Belmont areas.

Key highlights:

  • Outstanding silver and gold recoveries: Representative composite vein samples from the Murray and the Belmont areas returned recoveries ranging from 83.7 per cent to 96.7 per cent for silver and 95.9 per cent to 97.1 per cent for gold from flotation concentrates.
  • High-grade concentrate produced: Both composite samples produced high-grade concentrates, with grades of 6,954 grams per tonne (g/t) silver and 58.5 g/t gold from Belmont, plus 1,486 g/t silver and 12.6 g/t gold from Murray.
  • Conventional milling expected: The demonstrated recoveries were produced from a sample grind size of 80 per cent of particles passing 75 microns or smaller, which is typical in conventional milling processes.
  • Importance of gravity separation: The test work also showed that prior to flotation, gravity separation improved recoveries for silver and gold significantly at both Murray and Belmont.
  • Drilling at the Ruby discovery continues: A 650-metre stepout from the recent new vein discovery at Ruby is in progress, testing a large and undrilled geophysical anomaly.

Galen McNamara, chief executive officer, stated: "This work represents the first modern metallurgical testing done on our Hughes project in Tonopah, Nev. As expected, the results confirm the potential for very strong precious metal recoveries. The extremely high concentrate grades from the historic Belmont mine area are of particular interest. With our recent discoveries on the project at Ruby and Sapphire, we are well-positioned to continue to unlock value in and around this storied mining district. Additionally, we are preparing a fall drill program at Mogollon to test new targets and more information will be shared when planning is complete."

Metallurgical test work program summary

A scoping-level metallurgical test program was designed by Ausenco Engineering Canada Inc. and completed by Base Metallurgical Laboratories in Kamloops, B.C. Metallurgical testing was managed by the company and focused on refining multiple flowsheet options by conducting head sample characterization (assay and mineralogy) tests, cyanide kinetic leaching tests, rougher flotation tests, gravity tests and assay characterization of test work products (for example concentrates and tails).

Two representative composite samples of mineralized, epithermal-related vein material were selected from drill holes at the Murray and Belmont targets. These targets have seen the bulk of the recent drill testing by the company. HC-1 was an 11-metre composite sample from eight holes drilled into the Murray vein system of the Murray target, and HC-2 was a 13 m composite sample from 10 holes drilled into the Rescue vein system of the Belmont target. Samples were analyzed for head assay grades, which returned 224 g/t Ag with 2.05 g/t Au (HC-1), and 661 g/t Ag with 7.82 g/t Au (HC-2).

Metallurgical test work results are reported in the table entitled "Metallurgical test work results." The composite samples responded well to cyanide leaching tests. Whole-ore leach tests yielded silver recoveries of 86.1 per cent and 56.8 per cent, and gold recoveries of 90.9 per cent and 94.6 per cent. Producing a gravity concentrate prior to leaching increased the silver recoveries to 88.9 per cent and 86.3 per cent, and gold recoveries to 91.9 per cent and 94.6 per cent. Recoveries for silver and gold were optimized in HC-1 by adding a rougher flotation circuit after concentrating the sample by gravity. Leaching of this product from HC-1 yielded a silver recovery of 96.7 per cent and a gold recovery of 95.9 per cent. Leaching of the rougher flotation concentrate increased the recovery of gold to 97.1 per cent in HC-2, however, the silver recovery did not improve.

Flotation and leaching of the gravity concentrates have strong implications for maximum recoveries of silver and gold from the Murray vein, and for gold from the Rescue veins of the Belmont target. Future work will also focus on investigating grind sensitivities on silver and gold recoveries. As additional targets and veins are drilled by Summa, additional metallurgical test work will be initiated from new zones (for example, the Ruby target).


At Base Metallurgical Laboratories, the samples were ground in a two-kilogram (kg) rod mill to a 75-micrometre k80 grind size.

Head assay analyses were conducted via ICP-OES (inductively coupled plasma optical emission spectroscopy) following an aqua regia digest.

Gravity testing was conducted by centrifugal gold concentration using a Knelson MD-3 concentrator followed by cleaning on a Mozley C-800 table. The gravity concentrate was assayed for gold to extinction, and the tailings from the Knelson and Mozley table were retained for cyanide leaching.

Samples underwent rougher flotation collecting on four-timed concentrates to determine kinetic recover rates for Ag, Au and S (sulphur). The concentrates were reconstituted and leached in sodium cyanide, along with the rougher tailings for precious metal recovery.

Leaching tests were performed directly on whole-ore samples, as well as samples from gravity concentrates, and rougher flotation tailings and rougher flotation concentrates. Tests were completed in bottles on rolls which included four kinetic solutions measured after four, six, 24 and 48 hours of leaching. Products from the tests were assayed for gold and silver.

Mogollon project payment

In connection with Summa's option and joint venture agreement dated Aug. 21, 2020, with Allegiant Gold Ltd., with respect to the company's Mogollon property, the company intends to issue, subject to approval from the TSX Venture Exchange, 4,398,831 common shares at a deemed price of 50.47 cents per common share in order to satisfy the $1.65-million (U.S.) third anniversary payment. The common shares issued will have a statutory hold period of four months and one day from the date of issuance. Upon completion of the share issuance, the company will have satisfied phase 1 of the option and joint venture agreement, and have earned a 75-per-cent interest in the Mogollon project.

Qualified person

The technical content of this news release has been reviewed and approved by Mr. McNamara, PGeo, the CEO of the company and a qualified person as defined by National Instrument 43-101.

About Summa Silver Corp.

Summa Silver is a Canadian junior mineral exploration company. The company owns a 100-per-cent interest in the Hughes property located in central Nevada and has an option to earn a 100-per-cent interest in the Mogollon property located in southwestern New Mexico. The Hughes property is host to the high-grade, past-producing Belmont mine, one of the most prolific silver producers in the United States between 1903 and 1929. The Mogollon property is the largest historic silver producer in New Mexico. Both properties have remained inactive since commercial production ceased and neither have seen modern exploration prior to the company's involvement.

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