Click here for PDF: NI 43-101 El Rayo Project Report
Click here for PDF: Location, History and Geology
The El Rayo Project is located near the town of Guachinango in Jalisco, Mexico and is the site of some of the earliest silver mining in Mexico. The Project hosts numerous mineralized structures where silver, gold and lead were extracted from several underground mines, beginning in the mid-1500's.
Soltoro acquired the Project in 2005 and began drilling in 2007. From 2007 through 2010, Soltoro's primary focus was on the Las Bolas, Catarina-El Rayo and Highway structures, where much of Soltoro's current silver resource is located. Silver and gold mineralization have been traced in these structures over an aggregate distance of more than five kilometers.
In 2011, drilling focused on defining a resource on the high-grade La Soledad structure. Concession-scale geologic mapping, soil sampling and ground magnetics programs were also initiated in late 2011 and continue into 2014.Several targets were identified as a result of this work, including the Piedras Amarillas, Talayote and Mascotas areas (see below).
In December of 2011, Soltoro released an updated NI 43-101-compliant resource estimate, completed by Roscoe Postle Associates Inc. The resource estimate includes an updated estimate for the Las Bolas and Highway areas as well as the initial resource for the La Soledad structure. No work was done in the El Rayo gold zone so the El Rayo gold resource remains unchanged from the resource completed in June of 2011. The 2011 drilling, coupled with higher metallurgical recoveries for La Soledad, resulted in roughly a 25% increase in the measured and indicated silver resource at El Rayo. The results of the current NI 43-101 silver resource are reported below:
|Deposit Area||Cut-off grade
| Average Grade
|Contained ounces of Silver|
|Measured Mineral Resources|
|Indicated Mineral Resources|
|Total Measured and Indicated Resources|
|Las Bolas, Highway Zone & La Soledad||20||42.20||57.11||77,400,000|
|Inferred Mineral Resources|
|Total Inferred Mineral Resources|
|Highway Zone & La Soledad||20||0.58||65.51||1,180,000|
1. CIM definitions were followed for Mineral Resources.
2. Mineral Resources were estimated using prices of US$27/oz Ag. No credits are assigned for other metals.
3. Metallurgical recovery is assumed to be 72% of the contained silver for the Las Bolas deposit and Highway Zone,
and 80% for Soledad.
4. High silver values are cut to 400 g/t Ag.
5. Mineral Resources were estimated using a pit discard cut-off grade of 20.8 g/t Ag for the Bolas and Highway deposits,
and 18.72 g/t Ag for La Soledad deposit.
6. The numbers for tonnage, average grade and contained ounces of silver are rounded figures.
7. The Las Bolas, La Soleded and Highway Zone deposits are modeled at a minimum of 5 m vertical thickness of mineralization.
8. The above resources are constrained by a Whittle optimized pit shell and constitute 87% of total resources within a conceptual
open pit for the Bolas Structure, 89% of total resources for La Soledad Structure, and 64% for the Highway Zone.
9. Mineral resources, which are not mineral reserves, do not have demonstrated economic viability.The estimate of mineral resources
may be materially affected by environmental, permitting, legal, title, taxation, socio-political, marketing, or other relevant issues.
*NOTE A - During the third quarter of 2013, Soltoro concluded extensive metallurgical testing on the Las Bolas deposit and detected recoveries which Soltoro considers will have a negative impact on the resources established in the 2012 Resource Estimate Report and listed above. As a result, a new technical report is planned to take into account relevant recovery factors as well as all new exploration programs completed since the 2012 Resource Estimate Report above. It will update the silver resource estimates for Las Bolas, the Highway Zone, and La Soledad, as well as establish an initial resource estimate for the Catarina Mine.
In 2012 and 2013, Soltoro's focus was drilling known mineralization along strike and at depth, and testing anomalies identified through soil sampling and geophysics. In late 2012, Soltoro discovered high-grade semi-massive sulfide mineralization at depth at the Las Bolas deposit and extended that mineralization along strike at depth 200 metres to the southeast in early 2013. Due to market conditions, drilling was halted near the end of the first quarter of 2013. The remainder of 2013 and 2014 was spent reevaluating data and permitting future exploration activities.
Las Bolas & Highway Zone Primary Silver Deposits: The Las Bolas deposit consists of a tabular body of silver-bearing specularite-quartz breccia striking to the northeast and dipping to the northwest at 50 to 60 degrees. The mineralized breccia-vein ranges in thickness from around one metre to 40 metres with silver-bearing quartz-specularite stockwork of varying intensity occurring in the hanging wall. At Las Bolas, silver occurs in fine-grained sulphide minerals, such as acanthite, mckinstryite and aguilarite in quartz-specularite veinlets, often in close association with mimetite (lead arsenate) and vanadinite (lead vanadate) with very minor base metal sulphides. The breccia-vein has been drill-tested for more than 300 metres down dip from the surface and for over 1,000 metres along strike and shows little variation along strike or at depth.
Recent drilling at depth in the Las Bolas zone encountered a sulphide-rich zone near the base of the typically sulphide-poor breccia-vein and stockwork zone. Hole Ray12-152 averaged 278 g/t Ag and 11.5% Pb over 11.2 metres drilled width and was distinctly rich in galena and poor in specularite. The relationship of this mineralization to the typical sulphide-poor, specularite-bearing breccia-vein and stockwork mineralization is currently being investigated.
The Highway Zone is similar in composition, although somewhat more quartz-rich, and structural attitude to Las Bolas.The relationship between the Highway Zone and other mineralized zones of similar orientation is unclear but they are thought to represent en echelon structures.
La Soledad Primary Silver Deposit: In early 2011, Soltoro completed a surface trenching and sampling program followed by an initial four hole diamond drilling program to test the La Soledad structure. The results of this drilling were extremely encouraging and an additional drill rig was added to the program, such that 50 diamond drill holes totaling 8,968 metres were completed in 2011. With this drilling, Soltoro defined two mineralized zones within La Soledad structure: the Central Zone measuring 225 metres in length and the Western Zone measuring 150 m in length. The Central Zone has been drill tested to a depth of 250 metres below the surface. The Western Zone has been drill tested to a depth of approximately 100 metres below the surface and is open at depth.In 2012 and early 2013, Soltoro focused on the strike extensions of the La Soledad deposit. The extension of the Western Zone is complexly faulted and the relationship of this mineralization to the Western Zone is unclear as the intersections are high-grade, but narrow and the dip is distinctly different. Additional drilling is required to define this portion of the Western Zone.
At La Soledad, mineralization is hosted within a sequence of intermediate to mafic volcanic rocks consisting of massive flows and interbedded fragmental units. The mineralization is associated with hematite-altered structures in association with fine-grained silica as part of wider intervals of highly sheared and brecciated volcanic wall rocks. Silver occurs as freibergite and mckinstryite with lesser amounts of acanthite, aguilarite and furutobeite. Other metallic minerals consist of pyrite, sphalerite, galena with minor amounts of chalcopyrite and tetrahedrite-tennantite and traces of bornite, covellite and chalcocite.
Historic Catarina Silver Mine Area: The southeastern portion of the Catarina-El Rayo structure hosts the Catarina mine, where five high-grade silver ore shoots were mined by the Spaniards beginning in 1546. Mineralization at the Catarina mine was developed on several levels over approximately 500 metres of strike. In 2010, Soltoro completed detailed mapping and sampling along the surface portion of the Catarina vein. Results can be viewed at the link:
Click here for PDF: July 2010 Catarina mine trench location map with assay results
In late 2011, Soltoro completed seven diamond drill holes in the Catarina Mine area to test mineralization at depth. Drilling established that the Catarina mine area is not amenable to open pit mining.
In 2013, Soltoro collected 340 underground channel and chip-channel samples from over a 385 metre strike length on the main level of the Catarina mine.Phase 1 sampling was designed to better understand the geology of the Catarina mine area and confirm the historic silver resource estimate made by the Mexican government in the early 1980's. The best result was 11.57 metres averaging 449 g/t silver, 0.13 g/t gold and 3.54% lead. Complete results are presented in the Soltoro news release dated June 25, 2013.
In the third quarter of 2013, Phase 2 of the Catarina Mine sampling program was initiated and an additional 140 channel samples were collected from the main level. Highlights of this sampling include 1.30 metres averaging 646 g/t silver and 2.13% lead and 2.0 metres averaging 391 g/t silver and over 20% lead. Both of these channels are from near the northwestern end of the workings and may signal the presence of a previously unknown high-grade shoot beyond the current extent of the workings. Drilling will be required to confirm this.
The second level of the Catarina mine, the -50 level, occurs in two separate segments, both of which were flooded.Soltoro was able to partially dewater the eastern segment and collect 93 channel samples.Highlights of sampling from the -50 level include 1.1 m averaging 255 g/t silver and 0.25% lead and 2.2 m averaging 332 g/t silver 0.76% lead.
Piedras Amarillas Silver Discovery Zone: Over 15,000 soil samples have been collected from the El Rayo Property leading to the identification of several multi-element anomalies, including three parallel soils anomalies in the Piedras Amarillas area located approximately 1,500 metres east of the Las Bolas deposit. The anomalies range from 300 metres to 800 metres in length and 50 metres to 150 metres in width with silver values ranging up to 34 ppm. Follow-up sampling of the eastern soil anomaly identified a northeast-trending zone of quartz stockwork with associated hematite staining in basaltic wall rocks. At Piedras Amarillas there are a few small prospect pits but no evidence of historic mining activity as the zone sits primarily under pasture land and cultivated fields with little outcrop.Evidence suggests that the stockwork zone extends for nearly 500 m along strike but the width of the stockwork is not presently known because the area is largely covered by soil and outcrops are scattered. In 2012, 16 reverse circulation drill holes totaling 2,445 m were completed in the two soil anomalies at Piedras Amarillas. Most of the drill holes intersected low-grade silver values over modest widths but only one narrow, high-grade interval was intersected.
Mascotas Silver Discovery Zone: The Mascotas zone was discovered during geologic mapping as part of Soltoro's systematic exploration of the El Rayo land package. The Mascotas mineral system consists of at least five separate mineralized structures occurring within an area extending 600 metres northeast by 800 metres northwest located approximately five kilometres north-northeast of the main silver deposit area.
All five structures strike to the northeast, dip to the northwest at 55 to 70 degrees and vary in width from 2 metres up to approximately 10 metres. Mineralization in the Mascotas area shares many similarities with mineralization in the Las Bolas primary silver deposit including: 1) Broadly similar strike and dip; 2) Mineralization consisting primarily of an anastomosing network of quartz veinlets and breccia hosted by mafic to intermediate volcanic rocks; 3) Presence of yellowish-green quartz thought to be caused by the occurrence of mimetite and/or vanadinite in the quartz; 4) Hematite alteration interpreted to be hypogene in origin, and 5) Both areas are anomalous in silver, lead, arsenic, vanadium and barium.
A total of 59 samples were collected during the first phase of sampling, nine contained silver grades greater than 100 g/t Ag and 12 contained silver grades between 50 g/t Ag and 100 g/t Ag. The highest silver grade obtained during this phase of work was 264 g/t Ag.
In mid-2014, Soltoro submitted two rock samples to Transmin Metallurgical Consultants in Lima, Peru for preliminary metallurgical testing.
El Rayo Gold Deposit: Previous drilling identified a zone of gold mineralization one kilometre in strike length at the northwestern end of Catarina-El Rayo structure. At a pit discard cut-off grade of 0.35 g/t Au, the resource estimate for the northwestern-most 250 metres of the gold structure is reported by Roscoe Postle Associates Inc. as follows:
In 2013, Soltoro collected 340 underground channel and chip-channel samples from over a 385 metre strike length on the main level of the Catarina mine. Phase 1 was designed to better understand the geology of the Catarina mine area and confirm the historic silver resource estimate made by the Mexican government in the early 1980's. The best result was 11.57 metres averaging 449 g/t silver, 0.13 g/t gold and 3.54% lead. Complete results are presented in the Soltoro news release dated June 25, 2013.
Sampling of the -50 metre level will begin in the third quarter of 2013. If confirmed, this historic resource could add significant additional, high-grade ounces to the current NI43-101-compliant resource.
|Deposit Area||Cut-off grade (g/t Au)|| Tonnes
| Average Grade
|Contained ounces of Gold|
|Indicated Mineral Resources|
|El Rayo North||0.35||380||1.85||22,600|
|Inferred Mineral Resources|
|El Rayo North||0.35||365||1.61||18,900|
1. CIM definitions were followed for mineral resources.
2. Mineral Resources were estimated using prices of US$1,300/oz Au. No credits were assigned for other metals.
3. Metallurgical recovery is assumed to be 90% of the contained gold.
4. The Rayo Extension deposit is modeled at a minimum of 5 m vertical thickness of mineralization.
5. The numbers for tonnage, average grade and contained ounces of gold are rounded figures.
6. The above resources are constrained by a Whittle optimized pit shell.
In order to better understand the complex geologic relationships at the northwest end of the current El Rayo gold resource, Soltoro began a detailed exploration program in this area in late 2013.Two diamond drill holes and sixteen trenches tested soil and geophysical anomalies but did not locate the extension of the El Rayo mineralization. Of the sixteen trenches, only trench ERY-13 returned significant gold values consisting of 16.97 m averaging 3.45 g/t gold including 1.50 m averaging 20.6 g/t gold. Trench ERY-13 was previously sampled in 2009 as trench R2 and this trenching confirms the values obtained at that time. Trench R2 returned 19.5 m averaging 2.53 g/t gold including 7.5 m averaging 5.36 g/t gold and 1.5 m averaging 10.3 g/t gold. This work was followed-up by three additional trenches with the best result coming from trench ERY-19, which returned 24.00 metres of 2.09 g/t gold where mineralization remains open in both directions.
Soil geochemistry and ground magnetics west of the El Rayo resource area, followed by a limited trenching program in 2012, identified the La Ocotera area, which may represent the extension of the El Rayo structure. Values from trenching in the La Ocotera area include 1.01 g/t Au over 4.8 m and 0.91 g/t Au over 6.5 m.
Talayote Gold Discovery Zone: In the second quarter of 2013, the Company discovered the previously unknown Talayote gold target. Initial soil sampling detected several isolated gold anomalies in the area where follow-up geologic mapping and rock sampling revealed a series of northwest-trending quartz stockwork zones located approximately 1.5 kilometres southeast of the El Rayo gold deposit.Chip samples returned values up to 2.3 metres of 2.18 g/t gold including 0.50 metres of 11.40 g/t gold.
Exploration in 2014: Soltoro will complete a revised NI 43-101 technical report and silver resource estimate taking into account results from recent metallurgical testing and lower commodity prices, as well as include the initial resource for the Catarina mine. At the same time, we will develop a plan to permit and explore the deep sulfides at Las Bolas, the depth extension of the Catarina deposit and the northwestern extension of the El Rayo gold deposit.