Trevali intersects multiple broad intervals of high-grade zinc at the Santander Pipe target - system remains open for expansion
Tuesday, Dec 05, 2017
Trevali Mining Corporation ("Trevali" or the "Company") (TSX:TV)(LMA:TV)(OTCQX:TREVF)(FRANKFURT:4TI) announces results from its 2017 exploration program where directional diamond drilling continues to intersect multiple zones of high-grade zinc mineralization within and below the Santander Pipe target at its Santander Zinc Mine in Peru.

"From our initial discovery drill hole in February 2008, Trevali has enjoyed almost 10-years of accretive resource growth and replacement at Santander. Given the coarse style of the mineralization, absence of significant amounts of barren sulphide and location immediately adjacent to the mine infrastructure, the Santander Pipe forms a compelling high-priority target," stated Dr. Mark Cruise, Trevali's President and CEO. "The exploration team currently has two surface and two underground drill rigs expanding the mineralized system which remains to be fully delineated."


The Santander Pipe was continuously mined between 1957 and 1991 to a vertical depth of 480 metres below ground surface. Based on historical mine records the Pipe produced 7,993,105 tonnes of ore grading 10.88% Zn, 0.98% Pb, 0.31% Cu and 2.1 oz/t Ag during this period. Due to a combination of low commodity prices coupled with a general lack of development, mining ceased in high-grade mineralization and remains open for expansion at depth.

In 2011 Trevali completed five drill holes to compare and confirm the presence of mineralization versus historic drill results at the mid-levels of the Pipe. All holes intersected broad zones of mineralization (up to approx. 100 metres at 2.73% Zn) adjacent to and within the historic workings, within which are shorter high-grade intervals:

  • 11.25 metres grading 7.24% Zn, 0.49% Pb and 94.9 g/t Ag
  • 9.5 metres grading 8.88 % Zn, 0.64% Pb and 41.4 g/t Ag
  • 7.1 metres grading 14.15% Zn, 0.74% Pb and 135.9 g/t Ag
The Santander Pipe target, as currently defined, is a roughly cylindrical body with a diameter of approximately 120 metres. Mineralization in the upper half of the Pipe, from 0-to-230-metres below ground surface, is hosted within the Jumasha and Pariatambo limestones while the lower half occurs within more favorable and reactive limestones of the Chulec Formation.

In the upper half of the Pipe, massive to semi-massive sphalerite with accompanying silver-rich (argentiferous) galena, pyrrhotite and minor chalcopyrite mineralization occurs as an annular ring 6-20 metres thick surrounding a central stock of lower grade garnetiferous skarn and disseminated sulphides that typically range from 0.5 to 4.0% Zn and 0.4 to 1.5 oz/t Ag. Sulphide mineralization in the lower half of the Pipe (from 230 to plus-440 metres below ground surface) occurs as manto replacement bodies between 5 to 25 metres thick, similar to those reported here.

The high-grade mineralization within the Pipe is defined as robust and is controlled by an interplay of structure, favorable host lithology (clean and/or porous limestone units), and proximity to the primary fluid pathways. Based on results to date it represents a very attractive target capable of rapidly adding significant tonnages at relatively high zinc grades.


The first two holes testing the Pipe, SAN-0224 and SAN-0225, were designed to test the southern and central portions of the target respectively. As anticipated both holes intersected intense skarn alteration prior to intersecting broad zones of disseminated to massive zinc rich replacement mineralization.

SAN-0225B and SAN-0225C are daughter holes branching off the parent hole SAN-0225. They were designed to provide resource definition and confirm continuity of the mineralization encountered in SAN-0225 in the central portion of the currently defined Pipe.

SAN-0226, and daughter hole SAN-0226B, were designed to test the mineralization within the lower mine levels of pipe target, at similar vertical levels to currently defined Magistral mineralization, which also remains open for expansion.

Mineralization intersected in these holes is primarily sphalerite (+/- chalcopyrite) hosted within an intense garnet alteration halo. The relatively low quantities of barren sulphide gangue (pyrite and pyrrhotite) is anticipated to result in high recoveries and to produce a very clean zinc concentrate making the Pipe target metallurgically attractive. Several of the drill holes have also intersected late, lead and silver rich veins that cut earlier zinc mineralization. Additional drilling is required to understand the importance and geometry of these vein systems but as seen at the Magistral deposits they can form attractive high-grade targets in and of themselves.


For the remainder of 2017 additional exploration drilling will continue to test targets in and around the Santander Pipe. Surface drilling will also follow up on a variety of near-mine high priority targets along the two primary mineralization trends on the property. The underground drill program is advancing well at the Magistral bodies and is anticipated to expand the inferred resource in addition to upgrading inferred tonnages to measured and indicated status for future mine planning as part of Santander's rolling mine plan strategy.


On November 6, 2017 Trevali announced the results of a Preliminary Economic Assessment ("PEA") for Halfmile-Stratmat massive sulphide zinc-lead-silver deposits in the Bathurst mining camp of New Brunswick, Canada.

Under the base case PEA both the Halfmile and Stratmat deposits are fed to a new 3,000-tonne-per-day concentrator plant located at the Stratmat site. Results indicate positive economics with a preproduction capital expenditure of $231-million, a post-tax internal rate of return (IRR) of 19 per cent, post-tax net present value (NPV) of $99-million at an 8-per-cent discount rate, a mine life of 13 years with peak annual payable production of approximately 117 million pounds zinc, 35 million pounds lead, two million pounds copper and 766,000 ounces silver. The alternative case PEA examined the feasibility of transporting preconcentrated dense media feed (DMS) to the company's Caribou concentrator plant. This study indicates economic results with an estimated preproduction capital expenditure of $156-million, a post-tax IRR of 25 per cent, post-tax NPV of $116-million at an 8-per-cent discount rate.

Trevali has filed, both on SEDAR and its website, the technical report entitled "Technical Report on Preliminary Economic Assessment for the Halfmile-Stratmat Massive Sulphide Zinc-Lead-Silver Integrated Project Bathurst, New Brunswick, Canada" completed by SRK Consulting (Canada) Inc. and dated effective October 26, 2017.

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