Las Bolas Property Summary
Las Bolas one of the Golden Goliath properties in the Uruachic mining camp that are being optioned to Fresnillo PLC.
The property includes several claims in the area indicated below.
Golden Goliath Uruachic camp properties
The Las Bolas / Los Hilos Property
The Las Bolas / Los Hilos property covers a total area of 481.34 hectares and lies pretty much in the heart of the Uruachic district. Its dimensions are roughly 3.5 kilometres East-West by 2 kilometres North-South. The property hosts many old adits and shafts, including the extensive old Las Bolas workings and stopes.
An understanding of the geography of the property is extremely helpful in understanding the situation. A photo is given below to help with visualization. The Rio Uruachic runs north to south across the western side of the property resulting in a small valley. The elevation along the creek is about 1150 m AMSL. The slope on the east side of the Rio Uruachic rises to a small plateau at about elevation 1550m AMSL. There are many old adits that have been driven into this hillside. The lowest one is El Manto, which is very close to the Rio Uruachic. However most occur near the upper edge of the slope. These include the old Las Bolas workings, which are very extensive, as well as Gambusio, Frijolar, El Corazon, Guadalupana, and Providencia, going from north to south.
In the central plateau of the property, which is under cultivation by the local farmer, there are the remains of several small shafts. Most of these lie in the cultivated area and the Company has not tried to rehabilitate these as it would disrupt the small farming operation.
The adits, and we believe the shafts, were used to explore and exploit shear/vein hosted silver and gold mineralization. There are 12 known, steeply dipping vein “systems” that occur in three trends that run east-northeast. These structure often contain more than 1 single vein, but rather a swarm of shear hosted vein-like structures. Diagrams below show the 12 known vein systems.
On the east side of the property there is a north-south ridge. East of the ridge lies the Nopalera property. Near the south end of the ridge is the old Los Hilos mine workings, which runs east west. Several other much smaller old workings and pits occur along the ridge. The ridge hosts a different style of mineralization. In Spanish, the words ‘los hilos” mean “the threads”. This name has been given to the area because it is characterized by a flood of small veinlets and quartz filled fractures. There is a porphyryitic intrusive underlying the southern part of the ridge just south of the Los Hilos tunnel. The Los Hilos area is a different target style that the Las Bolas area. It is a disseminated bulk target rather than a vein style target.
When the company first started working on the property the focus of exploration was the rehabilitation, mapping and sampling of the adits on the west side of the property. Later work was done on the east side of the property, including the mapping and sampling of the old Las Hilos mine workings. Following this some drilling was done by Agnico Eagle, who concentrated their drilling in this area.
A field program during 2003 included geological mapping and sampling of the Las Bolas, Gambusino, Guadalupana, Corazon, El Manto and the Los Hilos Adits. Two soil sampling surveys (lines) were carried out and RC drilling for a total of 1,060.54 meters in 11 holes was completed.
During 2004 field work included road building, surface and underground mapping and sampling, a magnetometer survey, a petrographic study and a reverse circulation drilling program. A total of 1,917.22 meters in 13 RC holes was completed.
During the 2003 and 2004 RC drill programs, drill hole recoveries ranged from 44% to 66% with an average of 58%. Several holes were abandoned due to drilling problems or due to poor ground conditions within heavily oxidized and fractured rock.
Both 2003 and 2004 drill programs were designed to test geophysical targets and the down dip and strike extensions of known silver mineralized structures within mine workings and thereby determine whether the property has the potential for hosting an open pit or underground silver-gold deposit.
During 2006 a total of 11 Reverse Circulation holes were drilled for a total of 2,124.46 meters. Later in 2008 a diamond drill program that included 26 holes for a total of 3,586.51 meters was completed. During the 2008 diamond drill program, core recoveries were generally above 85%.
In 2009 the Company decided to do a preliminary Resource estimate on part of the property. The focus of this independent work was only a very small area around the old Las Bolas, Frijolar and Provedncia workings on the west side of the property where very encouraging results had been obtained in underground sampling and in drilling. Unfortunately, a substantial portion of the Reverse Circulation drilling has recoveries below 80% and could therefore not be including in the estimate. We repeat that the area included in the resource estimate is only one small portion of the west side of the property and it is based on limited information. No information from the east side of the property is included. The purpose was to get an idea of what we were working with.
The following is taken directly from the NI 43-101 compliant Technical Report by independent consultant V. Jaramillo P Geo. which was accepted for filing in 2009 and is available to the public in its entirety on SEDAR.
“A total of 537 rock chip channel samples from underground were included in the inferred resource estimate and only 5 diamond drill holes from the 2008 program were included. The underground rock chip channel samples from underground pertain to the following veins: “
Las Bolas Vein System = 429 samples
Providencia Vein = 31 samples
Frijolar Vein = 77 samples
“The Inferred Resources estimated at the Las Bolas – Los Hilos Property consists of a total tonnage of 478,000 tonnes with 434 g/t silver and 0.98 g/t gold. This Inferred Resource contains an estimated 6.7 million ounces of silver and 15,000 ounces of gold. The inferred resources are presented in the table below:”
Now that the Las Bolas / Los Hilos property is under option to Fresnillo PLC
The focus of work on this property will be up to them.
The central potion of the Las Bolas property hosts 12 know “vein Systems”, hosted in three main trends. These trends are labelled on the diagram below.
The 12 vein systems in the main Las Bolas area are reproduced below in a diagram taken from the NI 43-101 report on the property written by V. Jaramillo in 2009.
LAS BOLAS AREA 12 KNOWN VEIN SYSTEMS From 43-101 report by V. Jaramillo, 2009
The most explored of these 12 “vein systems” (shown above in red above) is the Las Bolas vein system, and it actually includes at least 7 discrete ”veins” (see below). These are not simple quartz veins, but shear/vein structures.
Las Bolas “Vein System” (one of the 12 ) From 43-101 report by V. Jaramillo, 2009
The largest old working on the Las Bolas property was developed to exploit the Las Bolas vein system. Within this tunnel, which is over 1,000 metres long, are areas where multi-level stopes exploited high grade gold and silver mineralization. Two of these areas, “station 19” and ”station 37” were reopened, remapped and sampled in detail by Golden Goliath. In the two slides below each assay number is actually the weighted average of 3 samples (hanging wall, structure and footwall). The overall assays given are the weighted averages of all of those weighted averages.
On the east side of the Las Bolas property, adjacent to the Nopalera property, lies the Filo de Oro zone. This area also contains several old workings, the biggest of which is the Los Hilos West tunnel, as well as widespread showings of disseminated mineralization. Topographically, Filo de Oro is a ridge rising above the plateau of the main Las Bolas area, and therefore as a whole it is an exploration target on its own, it has a very attractive low stripping ratio. This can be seen on the location plan and section given below.
Being an attractive bulk mining target, the Filo de Oro zone was the area of focus of the drilling that Agnico Eagle (AEM) during the two years that the property was under option to them.During 2012 AEM completed ten holes totalling 2,803 metres in the Filo de Oro zone. The 2013 program included a total of 10 short holes totalling only 930 metres and eight of these were also in the Filo de Oro zone. The bulk of the property, including most of the main area and all of the westernmost El Manto zone, which is known to contain high grade sulphide mineralization which appears to be in the form of a flat lying vein structure, was untested by them and warrants further work.
Location and Claims
The Las Bolas/Los Hilos property consists of seven claims totaling about 657 hectares located in the centre of the Uruachic camp at the intersection of thee major regional lineaments.
The Las Bolas/Los Hilos property is underlain by both the Upper and Lower Volcanic Units. The Lower Volcanic Series consists of gently tilted lavas, flow breccia, and tuffaceous rocks with a minimum thickness of 700 meters. It is conformably overlain by 100 to 200 meters of felsic latite volcaniclastic breccia. These units are overlain by the Upper Volcanic Series, which is a sub-horizontal volcaniclastic assemblage of mostly felsic ignimbrites and tuffs. The Upper and Lower Volcanic Series are separated by an unconformity that is manifest by a distinctive multi-lithic, poorly consolidated rubble zone of probable colluvial origin. Subsequent erosion formed a window exposing mineralized rocks of the Lower Volcanic Series in the Uruachic district.
Within the property the volcanic package reaches a thickness of approximately 700 meters from the bottom section near the Uruachic creek, where the El Manto Adit is located, up to the ridge top where Filo de Oro is located. The bottom contact of the volcanic pile lies unconformably over Precambrian basement rocks (gneiss). The volcanics are mainly andesitic tuffs, agglomerates and breccias of Cretaceous age, overlain by Tertiary rhyolites. Intrusive rocks are predominantly small stocks of diorite, granodiorite and andesitic dikes.
Las Bolas Fault-Fracture-Vein System:
Work to date on the Las Bolas property, including reverse circulation and diamond drilling, detailed underground mapping and sampling of the numerous old workings and surface work, has shown that the central to western side of the Las Bolas property is characterized by three main mineralized trends. These trends run northeast by southwest and are called the Las Bolas-Gambusino trend, the Frijolar trend and the Corazon trend (see map on this page).These three zones host numerous, extensive old adits, with their entrances on the west facing slope above the Rio Uruachic. Mineralization within these trends is characterized by steeply dipping, fracture vein systems, hosting silver and gold mineralization, with lesser amounts of lead and zinc. This mineralization is believed to be the result of a mesothermal lead, zinc, silver system that was then overprinted by an epithermal gold-rich system. In all there are 12 known vein systems on the property and seven of them are on the western side of the property. They are called vein systems as there are often multiple veins on each. For example, the Las Bolas vein system hosts at least 7 veins in close association (see 43-101 Report by Jaramillo 2009 on SEDAR).
Further to the west of the main Las Bolas tunnel entrance, at El Manto, the mineralization changes to a semi flat lying zone of higher grade sulphide mineralization. Relatively little work has been done on this area, but it is postulated that this mineralization could be related to the source of the oxide mineralization with the fracture/vein systems above and to the east. This manto–like zone has returned some spectacular assays, such as 9.87 grams/tonne gold with 3,090 grams/tonne silver (89.6 oz/ton), over some drill intervals.
Disseminated Bulk-tonnage Gold System
In addition to the fracture/vein hosted mineralization in the three northeast trending trends described above, about 1,100 metres to the east on the Los Hilos ridge different disseminated-bulk-tonnage gold mineralization system called Filo de Oro has been identified cross-cutting the three main mineralized trends. This zone was identified and explored after the completion of the 43-101 report on the Las Bolas property written by Victor Jaramillo (November 2009). This report, which is on file in its entirety on SEDAR, includes a resource estimation for the Las Bolas area of the property. However, the estimation is based only upon 1,554 of diamond drilling and detailed sampling of underground workings. The much more extensive Reverse Circulation drilling, could not be included as the recovery was below 80%.
Locally, high grade, gold dominant veins run through Filo de Oro. The roughly north-south trending Filo de Oro Trend also hosts numerous old workings. The zone has been defined for over 1,000 metres and is open at depth. Please see Figure (Location Map of Filo de Oro & Mosca de Plata Section) Preliminary underground sampling of the Mosca de Plata workings, within the Filo de Oro system, for example returned an average of 0.70 gms gold/tonne and 153 gms silver/tonne over its tested length of 46 metres. Nearby surface sampling returned an average of 0.82 gms gold/tonne and 40 gms silver/tonne for 79 samples. Additionally, 18 samples from a 40 metre long exposure of a 1.5 metre wide vein averaged 1.56 gms gold/tonne and 77 gms silver/tonne and in one location two contiguous samples across the structure averaged 10.2 gms gold and 257 gms silver/tonne. The Los Hilos tunnel itself averages 1.53 grams/tonne gold and 54 grams/tonne silver over the entire 208 metres of the main adit level.
In 2010 a program of diamond drilling was conducted on the Las Bolas property. The majority of the holes were collared on the eastern side of the property on the Los Hilos/Filo de Oro trend, but several holes were also completed within the three main trends on the western half of the property. The 2010 drill program consisted of 3,440 metres of drilling in 25 holes on the Los Hilos/Filo de Oro side (east side ) of the property and 999 metres of drilling in 8 holes on the Las Bolas (west side) area of the property.
The Los Hilos/Filo de Oro drilling was quite successful as it showed that both vein and disseminated precious metal mineralization was present over a wide area, with gold usually dominant over silver. Deeper, porphyry related, mineralization was also found in the southern end of the Filo de Oro trend, which could be of major significance with respect to further exploration.
The 2010 drilling on the west side of the property as it confirmed the strike extension of the three northeasterly trending mineralized trends and also showed that the mineralization is open to depth. This depth potential strengthens the possibility of the mineralization being related to the semi flat lying sulphide zone of the El Manto area.
Additional work by independent consultant Victor Jaramillo also shed light on the nature of the Las Bolas mineralization. In his 43-101 report he summarizes that he “believes that the Las Bolas-Los Hilos Property hosts an early stage mesothermal system of silver-lead-zinc veins followed by a later low sulphidation epithermal gold-silver event. Both systems are structurally controlled and confined mainly along fault zones as veins, silica stockworks and breccias.
Mesothermal vein systems are formed at considerable depths (from 600 m to 1000 m or more) by hydrothermal processes in a temperature range of 200°C to 300°C. The presence of dark gray quartz veins, cutting and brecciating the early silver-base metal mesothermal veins or oxide veins may be related to this later epithermal event. See image Banded iron-manganese oxide vein with quartz.
Jaramillo also states:
“In the author’s professional opinion, the property discussed in this report is of merit, and thus it is strongly recommended that a detailed exploration program, as outlined in this report, be undertaken.”
Las Bolas Station 19:
Previous grab samples had indicated the presence of high grade silver in the fault-fracture-veins system in station 19. In 2009 the company took 98 two-metre centered chip samples over the strike length of 45m in four sub-levels of this stope. The detailed sampling on the four sublevels of the stope defined a 45 metre long interval with a weighted average grade of samples 1.25 gms gold/tonne and 577 gms silver/tonne with an average vein width of 2.12 metres. Please see Figure Las Bolas Station 19.
Las Bolas Station 37:
About 200 metres further along the Las Bolas tunnel in the Station 37 stope area, similar work identified several high grade sections including a 30.6 metre length with a weighted average of samples 4.7 gms gold/tonne and 485 gms silver/tonne over an average vein width of 2.12 metres. The company took 137 two-metre centered chip samples across the veins as well as across the hanging wall and foot wall of the veins.
The planned follow up work for this area is to complete a new underground cross cut that will expose all of the veins in this area to allow for additional sampling to increase the resource as well as surface drilling in order to extend the proven strike length of the system.