Exploration
La Fortuna
Location
The La Fortuna property is located in the northwestern corner of the State of Durango, about 70 kilometers northeast of Culiacan. Culiacan is located 270 kms northwest of Mazatlan, a major port city, and 200 kms southeast of Los Mochis, also major port city.
History
Between 1991 and 1996, the San Fernando Mining Company Ltd. spent in excess of US$9.0 million developing the La Fortuna project. The company conducted an extensive exploration program, including detailed mapping and sampling of underground openings, and 121 closely spaced diamond drill holes for a total of 18,900 meters of drilling. Results were favorable and indicated that follow-up exploration and development work was justified.
Geology
The gold-silver-copper mineralization at the La Fortuna project occurs as disseminations, stockwork veinlets and fracture fillings. It is noteworthy that the degree of mineralization and therefore the grade of the ore is a function of the intensity of the fracturing.
The mineralized body is slab-like in form, ranging from 20 to 40 meters in thickness. It dip's to the west at approximatley 30 degrees. The lower part of the body rests on a healed breccia base while the upper part consists of quartz stringers and veinlets extending up into the hanging wall. The deposit extends approximately 200 metres in a north-south orientation and 150 metres in an east-west orientation.
Resource
In 1995, Fluor Daniel Wright of Vancouver, B. C. was commissioned to estimate the geological resource. The results of the closely spaced core drill program conducted by the San Fernando Mining Company Ltd., outlined a geological resource of 4,451,000 tonnes averaging 2.25 g/t gold, 29.9 g/t silver and 0.23% copper at a 0.5 g/t gold cut off grade (322,000 ounces gold, 4.3 million ounces silver, and 22.6 million pounds of copper). It should be noted that the historical assays and resources discussed above were calculated prior to the implementation of National Instrument 43-101 and do not comply with the current Canadian Institute of Mining, Metallurgy and Petroleum (CIM) standards and definitions for estimating resources and reserves as required by Canadian National Instrument 43-101 "Standards of Disclosure for Mineral Projects". Sufficient work has not been done to verify the historical assays and resource estimate to classify it as a current mineral resource and therefore this estimate should not be relied upon.
Fluor Daniel Wright's estimate of the open pit potential, at a 0.5 g/t gold cut-off grade, is 13,614,300 total tonnes, of which 10,698,000 tonnes would be waste, and 2,915,000 tonnes would be ore grading 2.25 g/t gold and 29.9 g/t silver. Fluor noted that further work would be necessary in order to confirm metallurgical parameters and costs.
Metallurgy
Previous metallurgical test work at the La Fortuna project was carried out by Colorado Minerals Research Institute (CMRI) and METCON to test the applicability of heap leaching using core samples which represented average grade indicated by the core drilling program. CMRI's conclusions showed that a ½" crush size produced a heap leach gold recovery of 64% with a 147 day leach cycle. This result was also verified by METCON's test work. Alternatively, conventional whole ore cyanidation utilizing a grind size of 100 mesh (149 microns) resulted in gold recoveries up to 97%.
43-101 Technical Report On The La Fortuna Project, Durango, Mexico
- May 15, 2007
(PDF, 3.21 mb)
43-101 Technical Report On The La Fortuna Project, Durango, Mexico
- October 21, 2008
(PDF, 1.14 mb)
 Click to enlarge |
Results from the drill program at the La Fortuna project located in Durango, Mexico. This drill program was managed under Castle Gold Corporation.
Results from the drilling were submitted by Castle Gold Corporationg. According to Castle's independent Qualified Person, the results from the 6 diamond drill holes, positioned to twin historical drill holes, correlated very well with the results from the previous exploration work completed at the site. Consequently, the validity of the historic data base has been confirmed as an adequate representation of the potential mineral resources contained within the deposit.
The twin hole drilling program follows recommendations made in a March 2007 Technical Report recommending such drilling to verify the historic data base. The historic database includes 121 diamond drill holes for a total length of 18,900 metres and eight levels of near horizontal underground development for a total of approximately 2,000 metres with each level separated by approximately 20 to 30 metres of vertical relief and five levels accessible by adits.
A number of attractive intersections were replicated from this 2008 twin hole drill program. These include:
- Drill Hole LF28-08 which intersected 21.2 metres grading 5.59 grams per tonne gold;
- Drill Hole LF30-08 which intersected 42.3 metres grading 3.76 grams per tonne gold; and
- Drill Hole LF61-08 which intersected 31.2 metres grading 5.52 grams per tonne gold.
It should be noted that within some intercepts there were large variances in both metres and/or gold grade. Most of the large variances in the intercept lengths were within relatively short intervals of mineralisation with the larger length intervals being much closer on a percentage basis. Most of the larger grade variations can be attributed to the nugget effect nature of the gold mineralization.
Comparison of Results - Historic and Twin Hole Drilling 2008 - La Fortuna Project, Durango, Mexico
| Twin Holes | Original Holes | Variance twin vs original |
||||||||
| Interval | Interval | |||||||||
| From (m) |
To (m) |
Length (m) |
Gold Grade (g/t) |
From (m) |
To (m) |
Length (m) |
Gold Grade (g/t) |
Interval Length (m) |
Gold Grade (g/t) |
|
| LF28-08 | 43.8 | 65.0 | 21.2 | 5.59 | 44.5 | 65.0 | 20.5 | 5.31 | 3.2% | 5.0% |
| LF29-08 | 28.0 | 34.0 | 6.0 | 2.83 | 30.3 | 32.1 | 1.7 | 3.45 | 244.8% | -17.9% |
| and | 38.0 | 76.0 | 38.0 | 2.19 | 38.1 | 75.3 | 37.2 | 3.19 | 2.2% | -31.2% |
| LF30-08 | 30.5 | 72.8 | 42.3 | 3.76 | 33.6 | 75.7 | 42.2 | 2.58 | 0.3% | 45.9% |
| LF40-08 | 43.1 | 46.0 | 2.9 | 3.85 | 42.2 | 46.2 | 4.0 | 0.76 | -27.5% | 408.6% |
| and | 58.9 | 60.4 | 1.5 | 2.44 | 62.2 | 66.2 | 4.0 | 4.21 | -62.5% | -42.1% |
| and | 86.0 | 100.0 | 14.0 | 3.43 | 86.5 | 102.5 | 16.0 | 3.02 | -12.5% | 13.4% |
| LF56-08 | 64.0 | 72.0 | 8.0 | 1.73 | 63.3 | 68.5 | 5.2 | 0.91 | 53.8% | 89.5% |
| and | 100.0 | 103.4 | 3.4 | 0.95 | 100.5 | 104.5 | 4.0 | 9.47 | -13.7% | -90.0% |
| and | 110.0 | 118.0 | 8.0 | 1.67 | 108.5 | 116.5 | 8.0 | 1.81 | 0.0% | -7.8% |
| LF61-08 | 14.0 | 16.0 | 2.0 | 0.49 | 15.4 | 17.4 | 2.0 | 0.60 | 0.0% | -17.8% |
| and | 32.0 | 34.0 | 2.0 | 1.35 | 33.4 | 35.4 | 2.0 | 0.36 | 0.0% | 270.9% |
| and | 70.8 | 102.0 | 31.2 | 5.52 | 68.2 | 103.2 | 35.0 | 3.68 | -10.7% | 49.9% |
| Total - Average | 180.6 | 3.58 | 181.8 | 3.29 | -0.7% | 8.8% | ||||
Qualified Person Comments/Quality Control Procedures
This press release has been reviewed by Mr. Toren K. Olson, P. Geo an independent consulting geologist. Mr Olson is a Qualified Persons under National Instrument 43-101. The design of the above described drilling program was supervised by Mr. Olson and the conclusions of the results from this exploration program are those of Mr. Olson.
Where analysed for gold, silver and copper, among other elements, drill core from this program was sawed in half with half of the core sent for preparation to ALS-Chemex in Hermosillo, Mexico and analysis conducted by ALS-Chemex Laboratories in Vancouver, Canada using gold fire assays with either Atomic Absorption Spectroscopy ("AAS") or gravimetric finish. Routine gold assays are by 30 gram fire assays and the repeat analyses have been carried out on pulps stored from the initial analyses.
