Horse Mountain

Summary

The Horse Mountain project consists of 139 claims covering 4.5 square miles (11.6 km2) along the Cortez Gold Trend in Lander County, Nevada (Figure 1). The property covers a two square mile (5.2 km2) zone of hydrothermally altered chert/quartzite, altered dikes and elevated Au / As / Sb / Hg in the upper-plate of the Roberts Mountains thrust. Below the thrust at 926 ft (282m), drilling intersects a carbonate horst containing oxidized, decalcified and gold-bearing carbonate rocks of the Roberts Mountains Formation. Significant drill results include 98 feet of 0.022 oz Au/t (27.4m of 0.754 g Au/t) in core hole BHM-001.

Geologic patterns recognized at the Horse Mountain project are similar to those documented within/proximal to bulk tonnage, profitable, disseminated gold deposits in Nevada (i.e. Pipeline, Cortez Hills, West Leeville, Gold Quarry). The patterns include: extensive zones of hydrothermal alteration and elevated metal values in upper and lower plate rocks, numerous high-angle fault zones, hydrothermally altered dikes, multiple metal events (disseminated gold and base metal), and thermal (metamorphic) alteration. These are positive attributes that upgrade the exploration opportunities at Horse Mountain. Miranda Gold geologists believe additional drilling is warranted within and along the carbonate horst margins to better evaluate this underexplored, sediment-hosted gold system.

In line with Miranda's joint venture business model, a new partner is aggressively being sought to continue exploration at Horse Mountain.

Location

Horse Mountain is located in the Shoshone Mountains, approximately 65 road miles (104 km) south of Battle Mountain, Nevada. Horse Mountain is on the Cortez Gold Trend, a northwest alignment of bulk-mineable, sediment-hosted gold deposits including Pipeline, Cortez Hills, Gold Acres, Cortez and Horse Canyon. The property is 10 miles (16 km) west-northwest of the active Pipeline gold mine, a +20 million ounce sediment-hosted gold deposit owned and operated by Barrick.

Geology

The Shoshone Mountains are underlain by Cambrian to Devonian sedimentary rocks, Jurassic to Tertiary intrusive rocks, and Tertiary volcanic rocks (Figure 2). Two distinct sedimentary rock packages occur on the property, separated by a low-angle, regional fault known as the Roberts Mountains thrust. The upper-plate of the Roberts Mountains thrust fault consists of deep water siliceous sedimentary rocks dominated by chert and quartzite. The lower-plate of the Roberts Mountains thrust fault is composed of shallow marine carbonate rocks. Lower-plate carbonate rocks are the preferred host for multi-million ounce gold deposits along the Cortez and Carlin Gold Trends.

Carbonate rocks of the Roberts Mountains and Hanson Creek Formations are exposed in the Horse Mountain window, northwest of the current property position. At the Horse Mountain project, upper plate siliceous rocks are exposed at the surface and cover prospective carbonate rocks (Figure 3). Drilling encounters hydrothermally-altered, gold-bearing lower-plate carbonate rocks at depth.

At surface, dozens of west-northwest, northwest, northeast, north-south and east-northeast striking faults transect the property. Mapping indicates northeast and northwest-striking faults focus hydrothermal alteration, igneous dikes and zones of elevated gold, arsenic and antimony in a 2,000 by 6,000 foot area (610 by 1,830m) (Figure 4). Within this area, faults create pervasive zones of broken/shattered upper and lower plate rocks. Pervasively broken rocks are an important precursor for the formation of large, sediment-hosted gold deposits. Collectively, these observations will help guide future drilling.

Figure 4 shows an oxidized and bleached upper plate cherty mudstone cut by a west northwest-striking hematite quartz vein. A rock sample from this exposure returned low level gold, and enriched concentrations of arsenic, antimony and mercury.

Exploration History

Previous work by Phelps Dodge defined a near-surface, upper-plate hosted, low-grade gold occurrence at the Rum Dreams prospect. Gold mineralization occurs with quartz veined, brecciated, oxidized and silicified chert and quartzite. Lamprophyre dikes occur in this gold zone. Rum Dreams may represent up-dip, structurally-controlled leakage from a larger gold system at depth. Similar upper-plate gold occurrences have been documented flanking the five million ounce West Leeville deposit on the Carlin Trend.

In the mid-1990's, drilling by Pathfinder and High Desert Minerals targeted carbonate horsts, uplifted blocks of favorable host rock, beneath the Roberts Mountains thrust fault. Carbonate horsts are well-documented features that control some large, sediment hosted gold deposits in Nevada. Drill hole MC96-08 intersected 30 feet (9.1m) grading 0.025 oz Au/t (0.856 g Au/t) from 940 to 970 feet (286.5 to 295.7m) in oxidized, decalcified and clay altered silty limestone interpreted as the Roberts Mountains Formation. The hole was lost due to poor drilling conditions at 980 feet (298.8m).

Joint Venture Exploration

In mid-2005, Barrick completed geologic fact mapping and gravity over the entire property. Later in the year, these data guided the placement of two vertical drill holes that totaled 3,126 feet (953m) (Figure 5). Results of BHM-001 are summarized below:

BHM-1, a 1,641 foot (500m) core hole to offset MC96-08, intersected 98.2 feet of 0.023 oz Au/t (29.9m of 0.788 g Au/t) from 926.2 to 1024.4 feet (282.3 to 312.3m). Gold mineralization is hosted in strongly decalcified, oxidized, clay altered and brecciated Roberts Mountain Formation silty limestone. Elevated arsenic, antimony and mercury occur with the gold mineralization (Figure 6). This gold system remains open in all directions (Figure 7).
Drill hole BHM-001 confirms the presence of a hydrothermal gold system at the Horse Mountain property. The hole intersected vertically-extensive zones of oxidation, clay alteration and pervasive fracturing in both upper and lower plate rocks. The hole confirms the carbonate horst interpretation indicated by hole MC96-08 (Figure 7). Rocks throughout the hole contain spotted hornfels (metamorphic) textures. Hornfelsed sedimentary rocks are known to host economic concentrations of gold in the Cortez Hills, Pipeline, Gold Acres, Gold Quarry, Bluestar/Genesis and Deep Star gold deposits. Miranda geologists are encouraged by these results.

In 2006, Barrick completed 8,650 feet (2,636.5 m) of reverse circulation drilling in three vertical holes (BRH-003, BRH-004 and BRH-005). The holes were designed to test for gold-bearing feeder faults where they intersect favorable lower-plate carbonate rocks. Drill hole sites were selected based on gravity, surface geochemical anomalies and geologic mapping. Significant gold-bearing intervals include 90 feet of 0.022 oz Au/t (27.4m of 0.753 g Au/t) and 50 feet of 0.017 oz Au/t (15.2m of 0.567 g Au/t) in drill hole BHM-005. Drill holes BRH-003 and BRH-005 are summarized below.

Drill holes BHM-003 and BHM-005 were drilled 1,440 feet (440m) and 1,835 feet (560m) southeast of BHM-001, respectively. The holes targeted lower-plate carbonate rocks beneath strong upper-plate alteration, anomalous surface gold mineralization, northeast-striking faults and altered dikes at the Rum Dreams prospect. BHM-005 intersected six separate 0.011 to 0.022 oz Au/t (0.377 to 0.753 g Au/t) zones over thicknesses of 25 to 90 feet (7.6 to 27.4m) in upper-plate chert and lower-plate carbonate rocks. BHM-003 intersected 20 feet grading 0.013 oz Au/t (6.1 m of 0.440 g Au/t). Arsenic, antimony, mercury and thallium values are strongly enriched in these gold zones.


Barrick terminated the Horse Mountain Venture Agreement in July 2007. In total, Barrick spent US$872,000 and completed 11,776 ft (3,590m) of drilling in five holes. This work has provided Miranda with vital information for understanding the structures and mineralization on the project.

Figure 6 shows clay altered, decalcified, oxidized and pervasively broken silty limestone from BHM-001. The interval from 997 to 1,016 feet assayed 0.026 oz Au/t, 830 ppm arsenic, 8ppm antimony and 3.8ppm mercury.

2008 Plans

Miranda believes high quality exploration targets remain to be drill tested at Horse Mountain. The company is actively pursuing a joint venture partner for the 2008 exploration season. Digital data packages are currently available for review.