Troy

NI43-101 Report

Press Release (Miranda Gold Corp), Nov 5, 2004


Summary

The Troy Property is located in the Grant Range of northeastern Nye County, Nevada in the Humboldt National Forest.  It is approximately 150 km east of Tonopah, Nevada and 230 km north of Las Vegas.  The property consists of 11 mineral claims covering approximately 91 ha (220 acres) on the western side of the Grant Range, east of Railroad Valley.

Troy Location Map                Troy Detailed Location Map
  Location Map                                                             Detailed Location Map

Geology and Mineralization

Troy’s historic underground workings are reported to exploit oxidized shear zones internal to a large bull-quartz vein. Historic production and exploration resulted in over 800 m of underground drift in the Locke Mine from 5 different adits in a 300 x 200 m area.  The property has not been drilled and no modern exploration has been conducted.

 
Troy Surface Au Adits
Troy Surface Au Adits

 

An interesting highlight of the property is represented in rock chip gold assays as high as 794ppm (25 opt) gold, with nine rock chip samples from Troy’s underground workings assaying above 40ppm (1.16 opt) gold.

 

Troy Underground Gold Values                     Troy Underground Au Values -Detailed
  Underground Au Values                                                    Detailed Underground Au Values


 

Troy Regional Geology

 


The workings of the Locke mine are driven predominantly within the large quartz body that is at or near the contact of carbonate rocks in the hanging wall and a granite intrusion in the footwall. The limestones vary from massive, medium gray and re-crystallized to very dark, strongly carbonaceous and sheared rocks. Apparently the carbonate section is Cambrian age. Intrusive rocks are presumed to be Tertiary but may be older.



  Troy Regional Geology

West of the Locke mine the large quartz body thins and in places is not present but its position at the contact of the carbonate section and the intrusion is occupied by a consistent mylonite zone even where quartz is absent. The mylonite zone strikes NE-SW and dips approximately 20 degrees SE. There appears to be a fault with similar attitude at the base of the high limestone cliffs south of the Locke mine. Significantly, the thickest portion of the massive quartz body occupies a domed inflection in the limestone-granite contact.  The contact is dominantly if not exclusively structural. Faults at the contact are well-exposed underground. It appears that the thick, obvious quartz body is related to regional-scale faulting and mylonitic shearing and it is important to note that this massive quartz is typically barren and does not represent the primary target at Troy.

Troy Outcrop Geology
Troy Outcrop Geology



Ore Shoots in the Locke Mine

Within the large quartz body various workers have obtained gold assays of up to approximately 3 opt over several feet and multi-ounce gold in more selective samples. Gold and silver mineralization occurs with pyrite and arsenopyrite, and lesser sphalerite and galena.  Zones of strong limonite or manganese staining tend to display stronger precious metal values.  Grayish, vaguely banded, cellular quartz distinct from and cross-cutting the bull quartz observed locally suggests that a secondary quartz event took place after emplacement of the main bull-quartz vein.  Higher grade values are isolated and on historic sample maps appear to be almost randomly scattered through the massive quartz, however, careful examination reveals that the higher grade portions of the mine are along north-south striking, shallow easterly dipping faults within the larger, massive quartz body. These discrete ore shoots have strong iron-oxides (after sulfides) and have a cellular/vuggy, grayish to dark red appearance. It is obvious from stope development that this is the material that was sought during historic mining.

Troy Bat Adits 1.2oz

 

 

 

 

 

 

Bat Adit 1.2oz

Three such structures appear to be present within the existing workings: These fault-veins have named by previous workers the A vein and B vein from east to west respectively.   A third poorly defined, structure appears to be present at the western end of the mine area above an ore chute system. The B vein in the Locke Mine is apparently the same mineralized structure that is exposed in workings on a prominent ridge approximately 500ft west of the main Locke mine portal. While the ore bodies are not proper veins, and often can be characterized visually as fault zones, for convenience sake they can be referred to (from east to west) as A, B and C veins consistent with earlier report nomenclature. Further sampling should illustrate the nature of the “veins” and whether they represent a consistent recognizable secondary quartz event superposed on earlier bull-quartz.




Troy Underground ABC Veins

 

 

 

 

 

 

Troy Underground ABC Veins

 

The north-south, east dipping ore-bearing structures are cut off by a shallower fault at the hanging wall of the massive quartz body. In the main Locke mine the hanging wall fault above the quartz body has a variable strike and appears to increase in plunge downward to the south giving it a folded and domed appearance. This fault may truncate the “A” vein down-dip and to the east with probably a minor offset. Whether the ore target extends into the hanging wall limestone and the foot wall intrusion is unconfirmed: Regardless, structures at the top and bottom of the quartz mass will have cut it off and displaced it somewhat. Stope widths are commonly 6 feet (2 meters) or slightly more.

Accounts of historic production report mill head grades of averaging 0.345 to 0.571 ounces per ton gold during the period from 1948 to 1950.  Total production is probably less than 1000 ounces of gold.  This is presumed to be primarily from stopes developed on the “A” vein.



Target Discussion

The target at Troy is for a mesothermal “fault-vein” gold system overprinting the erratically mineralized bull-quartz vein that has been the focus of historic underground drifting. Multiple, discreet, sub parallel stacked vein targets are suggested by the “A”, “B” and “C” veins mapped in underground workings.

The style of gold-mineralization at Troy can be cautiously called Pogo (Alaska)-like in that:

  1. gold and bismuth are associated suggesting a magmatic source,
  2. the main gold event appears temporally and possibly tectonically distinct from an earlier metamorphic (mylonitic) fabric enclosing the earlier main bull-quartz vein,
  3. gold bearing fault-veins (fault zones with secondary quartz (?)) are shallow dipping.

The Locke mine has not been tested by drilling. As an intrusive associated mesothermal gold system, if preliminary drilling shows that the north-south striking, east dipping series of productive fault-veins extend to depth below the south dipping bull-quartz body, there is good potential for the discovery of significant gold mineralization down-dip and laterally from the known workings.

District scale mapping also has a reasonable prospect of resulting in discovery of new occurrences. Although past production has been small, there has not been any modern attempt to discover resources in the Locke mine area.

It is difficult to estimate the size potential of the targets from existing underground workings but it is certainly reasonable to expect the mineralized structures to continue down-plunge for at least a few hundred feet, and to have substantial lateral extent.  Structures at the top (as observed at the upper surface in stopes) and probably at the bottom of the bull-quartz mass will  offset productive fault-vein projections into the limestone hanging wall and the granite footwall contact.

The thickness and attitude of the three recognized ore-grade bearing fault-veins (A, B, C)  targets make them potentially amenable to underground mining if suitable high-grade distributions in the shoots (comparable to other mesothermal gold veins)  result in the upper end of or better than recorded mill-head grades (0.571 opt gold) and ore shoot continuity and depth and lateral extent can be demonstrated by a preliminarily by a modest and relatively shallow angle drill program.



Exploration Discussion

Miranda is seeking a joint venture partner for the Troy Project to conduct exploration in return for majority equity.

An exploration program for Troy should include detailed underground geologic mapping should be done with emphasis on structural relationships. In conjunction with the mapping program a detailed sampling program should be done, particularly in the historic stopes.

Diamond drilling of targets to adequate test high-grade on tight spacing from surface is suggested. While much of the rock is competent, the mineralized quartz will probably present modest drilling problems.

Miranda has completed limited underground mapping and sampling to resolve productive veins and to confirm and project inferred controls to high-grade. A simple 3D model derived from surface and underground mapping and sampling has been constructed in order to target high grade zones as well as fault and vein extensions.  Several proposed drill-holes have been planned and can be visualized in the 3D model.


Troy Proposed Drill Holes

 

 

 

 

 

 



Troy Proposed Drill Holes


Summary of geochemical statistics for underground rock chip samples with gold >0.1 opt. Summary statistics for the 23 ore grade samples is shown in Table.


 

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