Come By Chance Videos
Come By Chance – Gold-Copper
Large Copper/Gold Porphyry Deposit Target
Belmont is performing a systematic approach for proving up a large copper-gold porphyry model on the Come By Chance property.
The CBC Property located three kilometres to the southeast of the Phoenix deposits (580 Mlbs. of copper and 1.4 Moz. of gold produced) on a comparative geological trend.
Hosts skarn, epithermal, and massive sulphide mineralization; typical mineralization associated with copper/gold porphyry deposits.
Skarn mineralization with elevated copper values occurs in many locations, with epithermal zones of alteration and quartz veining
A small circular lake with a highly anomalous arsenic content centered between two major faults, appears as a hydrothermal or a collapsed breccia developed from an underlying intrusive in a volcanic environment.
LIDAR Survey Supports Copper-Gold Porphyry Model
The location of the intrusive is supported by the results from the recent Lidar survey which clearly showed a series of radiating faults from the lake and obscure ringed faults surrounding the lake.
These faults were likely developed from a rising intrusive and were instrumental as the means of mineral laden hydrothermal fluid transport from the intrusive to create the localized skarns.
What is a Lidar Survey?
The principle of LIDAR is a laser rapidly emitting light pulses that penetrate vegetation and topsoil which are reflected back providing a very high-resolution “bald earth” digital elevation model (DEM)
Lidar is an effective, low cost method of accurately mapping the bare-earth surface (i.e. the ground surface as it would appear stripped free of vegetation) and showing centimetre-scale variations in surface elevation. It has many uses in geological exploration, including identifying the location and distribution of historic pits and other areas of disturbance which can then be ground-truthed. Lidar bare-earth data can also reveal linear topographic low features. These may coincide with the surface trace of fault zones that may be important controls to mineralization.
High Resolution Magnetic Survey Further Supports
Copper-Gold Porphyry Model
Belmont’s detailed, low-level magnetic survey of the CBC property has provided a greater indication of the volcanic caldera.
The indicated caldera is supported by a one kilometre diameter magnetic low bounded by the northwesterly trending Eagle Mountain Fault to the southwest and a the Lind Creek fault to the northeast.
The magnetic survey also revealed cross-structural locations formulated by major structures. The significance of the cross-structures is primarily that these locations would be prime locations for hydrothermal breccia zones in revealing mineralization transported from the mineralized intrusive porphyritic intrusive responsible for the caldera, the skarns, and other types of mineral deposits.
The results of the magnetic survey have advanced the exploration of the CBC Property to specific locations for the next stage of exploration to ultimately locate the porphyry copper-gold intrusive by diamond drilling.
The Importance of “Brecciation”
Hydrothermal breccias usually form at shallow crustal levels (<1 km) between 150 and 350 °C, when seismic or volcanic activity causes a void to open along a fault deep underground. The void draws in hot water, and as pressure in the cavity drops, the water violently boils. In addition, the sudden opening of a cavity causes rock at the sides of the fault to destabilise and implode inwards, and the broken rock gets caught up in a churning mixture of rock, steam and boiling water. Rock fragments collide with each other and the sides of the void, and the angular fragments become more rounded. Volatile gases are lost to the steam phase as boiling continues, in particular carbon dioxide. As a result, the chemistry of the fluids changes and ore minerals rapidly precipitate. Breccia-hosted ore deposits are quite common.
The morphology of breccias associated with ore deposits varies from tabular sheeted veins and clastic dikes associated with overpressured sedimentary strata, to large-scale intrusive diatreme breccias (breccia pipes), or even some synsedimentary diatremes formed solely by the overpressure of pore fluid within sedimentary basins. Hydrothermal breccias are usually formed by hydrofracturing of rocks by highly pressured hydrothermal fluids. They are typical of the epithermal ore environment and are intimately associated with intrusive-related ore deposits such as skarns, greisens and porphyry-related mineralisation. Epithermal deposits are mined for copper, silver and gold.
Greenwood-Republic Mining Camp
Lidar Survey & Mineralized Showings
Magnetic Survey & Mineralized Showings
Conceptual Model for Styles of Epithermal Gold-Silver, Breccia and Porphyry Copper Mineralization
Come By Chance Brecciation
Explosive hydrothermal brecciation. The interesting feature is the light grey fragments which appear the color of arsenopyrite (FeAsS), a mineral that can also can be associated with significant amounts of gold
The brecciated quartz veins indicate the iron content was derived from metamorphism caused by the quartz intrusion; although the iron may have been emplaced at various stages.