We recently
took a 4,000 kilometre, 7 day drive from Ontario to
Nevada to visit the Pamlico Ridge property, owned by Newrange Gold. The Project
is located just outside of Hawthorne in Mineral County and it sits within a
geological feature known as the Walker lane Trend. It also sits on the Pancake
Range Lineament which is a well known gold conduit that is host to several
mining operations. One of which happens to be the Kinross Gold operation at
Round Mountain.
Nevada is host to several operating gold mines and in 2018, the state of Nevada produced 5,581,160 troy ounces of gold. That accounts for 78% of the gold production in the United States and 6.3% of the world’s production. Needless to say, it is one of the largest industries in the state of Nevada. So when we set out to Nevada to see the Newrange Gold property we also aimed to find out what drives the mineralogical forces at play in the State of Nevada.
Pamlico Ridge, Hawthorne, Nevada
Here is a brief history of the Pamlico District , which can also be found on the Newrange Gold website.
Discovered about 1884, the Pamlico District quickly became known as one
the highest grade gold districts in Nevada. The earliest record of mining in
the area dates back to 1885. Subsequent high-grade underground mining exploited
many veins in the district through numerous inclined shafts and adits. Since at
least 1900, the Pamlico Project has been tightly held by family groups and
limited modern exploration has been done since.
Like many districts of the time, production was shipped to custom mills
in existing mining districts such as Aurora and the Comstock Lode, the
recovered metal often being inventoried as production from those districts
rather than from the actual district of origin. The United States Geological
Survey estimates production from the district between 1885 and 1900 to be
roughly 50,000 ounces of gold.
Approximately 300 adits, spread across the property, remain as a reminder of what once was a wealthy mining community. Walking and crawling through these drifts, man ways and stopes really gives you an appreciation for how hard the miners worked to get the gold out of the mountains. The scale of the underground workings was impressive to say the least, especially considering the tools they had to work with. The mining appeared to be a lot easier than what we see in Cobalt due to the fact that on this property, you could mine with a pick and a shovel with very little need for drilling and blasting.
It’s important to understand the geological forces at play
in Nevada before we discuss Pamlico any further. One of the most important
aspects to consider is the proximity to the San Andreas Fault system. The
state of Nevada has had a very complex and violent geological past and
highlighted below are some of the features and occurrences which allowed Nevada
to be one of the highest gold and silver producing districts in the world.
The San Andreas Fault
The San Andreas Fault system is one of the most well known faults in the world. This system runs roughly, 1200 kilometers on a Northwest/southeast trend through the state of California and along the Pacific coastline. This is where the Pacific Plate and the North American Plate meet to form a transform plate boundary. This is when two plates are sliding past one another instead of crashing into each other like in a subduction zone fault. Transform plate faults are often violent when they shift but overall have very little effect on the landscape aside from the gouges it has left behind in California. We have to go back to an earlier time, before the formation of the San Andreas Fault to understand what shaped the west coast of the United States.
The San Andreas Fault only came into existence approximately 30 million years ago, when The Pacific Continental Plate and the North American Continental plate first met. Prior to this, another oceanic plate called the Farallon Plate, was disappearing beneath the North America plate at a subduction zone. This plate boundary is ultimately responsible for the formation of the Sierra Nevada mountain Range and the coastal mountains of California. Furthermore it was the driving force behind the many fault systems, mountain ranges, ignimbrite fields and caldera complexes that littered the California/Nevada landscape long ago.
Calderas in Nevada
As a result
of the shifting Tectonic plates along the San Andreas fault (Farallon
Plate/North American Plate) system, calderas were formed throughout many parts
of Nevada. Calderas form on micro plates where the earth’s crust becomes very
thin as a result of The Oceanic Crust (subduction plate) moving under the Continental
Crust. This creates a convection current which produces an anomaly called a
mantle wedge. This in turn brings super heated magma much closer to the surface
where it reacts with ground water to lower the melting point of the overlying
rock layer. It’s the volcanic equivalent to the perfect storm which creates
conditions for massive volcanic eruptions.
After the eruption the magma chamber often collapses on itself, creating
the caldera. These events were very
common to the east of and parallel to the San Andreas Fault millions of years
ago.
Nevada is
host to 3 other major systems which had explosive silicic activity, two of
which; The Western Nevada Caldera’s and
the The Central Nevada Caldera’s extend into the northern part of the Walker
Lane Trend while the the Indian Peak–Caliente caldera complex spans across the
Nevada border and into Colorado These calderas create hydrothermal systems
which are in part responsible for Nevada’s highly mineralized geology which is
no surprise considering there have been 6 identified caldera forming events
with lulls of 2-4 million years in between in the last 25 million years.
These systems originated closer to the Sierra Nevada mountain range and over time have moved east/north east as the earth’s crust shifts towards to Pacific Ocean. Over Millions of years geological forces created a track of alteration over the Nevada Landscape which can be seen in the Mcdermitt Volcanic field situated just North-East of Reno. This caldera complex is considered to be the point of origin for the world’s largest magma reservoir, which now rests under Yellowstone Park. This caldera complex is situated mostly in Wyoming and crosses into both Montana and Idaho. In recent years it has been a hotbed of activity but that’s for another article.
Chronology of Volcanism, Stanford University
Walker Lane Trend
The Walker Lane trend is essentially a fault system parallel
with the San Andreas Fault that lies east of the Sierra Nevada Mountain chain
and was created by the pressure between the North American and Pacific plates. Stanford geologist Amos Nur co-authored a
paper in the late 1980s speculating that the San Andreas Fault might be looking
for a new outlet within the Nevada desert. Not more than a few years later, a
7.3-magnitude earthquake near the town of Landers, California, supplied
compelling evidence of a network of faults that geologists had not previously
identified which connected the Eastern California Shear zone and the Walker
Lane Trend. This would ultimately provide a better understanding of the Walker
Lane Trend and offer some insight to the regions geology.
For over 100 years the entire Walker lane stretch has
produced significant amounts of gold and silver amongst other metals even
during a time when there was limited understanding of the driving forces that
fed the system in the first place. Today the Walker lane is host to a number of
producing mines and the geological features are far better understood which has
opened up new opportunities within past producing mining camps like the Pamlico
Ridge property.
Pancake Lineament & Local Mining Operations
The Pancake Lineament is a very important regional feature
as it is a known conduit of gold mineralization that crosscuts the Walker Lane
Trend. It is also host to a number of producing and past producing mines, Round
Mountain alone has produced over 10 million ounces of gold. A few other known
mining operations along the pancake trend are The Bodie, Aurora and Borealis
mines, and they have produced good numbers of their own. Bodie is more of a
Historic tourist town at this point since it was abandoned in the early 1900’s.
However, in its prime Bodie produced over 34 million dollars worth of gold.
Round Mountain Mine-Kinross
The Round Mountain deposit is a very large, epithermal,
volcanic-hosted hot springs type of precious metal deposit along the margin of
a buried volcanic caldera. The intra caldera collapse features and the
localized faulting along the pancake lineament which provides a major
structural conduit for gold bearing hydrothermal fluids. Gold mineralization
appears to be associated with Quartz, adularia, pyrite and iron oxides. Gold is
mainly found in shear zone fractures, the veins and dissemination typically
occurs within the more permeable units of rock generally progressing through
clay creating narrow vein structures. They currently use their brand new 9
million square foot heap leach pad and a Vertical Carbon-in-column Plant to
extract their gold which is a very low cost method of extraction. I could go
into more detail but there is not much point as you will see as we continue.
The relevant points have been covered.
Aurora-Hecla Mine
The Aurora property is a 12.6 square-mile section of land
and located in the northeastern portion of the Bodie Hills in Mineral County,
approximately 105 miles southeast of Reno, Nevada. This region is an epithermal
gold-silver deposit, also within the Walker Lane and along the Pancake Range
Lineament which offer potential for further discoveries.
Historic production of about 1.9 million ounces of gold
occurred on the property from an anastomosing system of banded quartz, adularia
and sericite epithermal veins. Three stages of veining have been identified at Aurora,
beginning with early coarse-grained quartz-dominate vein stage followed by a
banded quartz-sericite-adularia veining stage with electrum, silver sulfides,
sulfosalts and base metal sulfides, and lastly a coarse-grained quartz veining
stage. A late stage calcite overprint is also observed with vug-filling coarse
calcite.
Borealis Mine-Radius Gold
Currently owned by Radius Gold, the gold deposits in the
Aurora-Borealis-Bodie district occur as both high grade vein-hosted low
sulphidation deposits and as high-sulphidation alunite-kaolinite gold-deposits.
Total historical precious metal production along this approx. 32 kilometer
trend, from the mid-19th century to the mid 1990s, has been estimated at 4.0
million ounces of Au, and 11.2 million ounces of Ag.
Both oxidized and gold-sulphide deposits occur within the
district, with gold-sulphide mineralization occurring at the bottom of most
pits, the most significant of which is beneath the Freedom Flats deposit.
Previous operators of the Borealis mine also believe that potential high-grade
feeder structure remain beneath existing pits. Drilling of these zones has
intercepted spectacular grade and thickness, in particular, the Freedom Flats
area
Pamlico Property- Newrange Gold
Looking at the geological controls of the Pamlico property and understanding how they correlate with the local geology along the Pancake lineament and the Walker Lane Trend is very important to understanding the deposit. In my opinion there are more comparables to the Round Mountain deposit than some of the other projects on the Pancake Lineament but ultimately more data is required to say that with any certainty. Below is the geological description of the Pamlico Ridge property.
“The Pamlico deposit is a
high-grade structurally controlled gold dominated, epithermal system. Deposits
of this class often have very robust economics and are less prone to adverse
sensitivities due to swings in metal prices as evidenced by currently operating
mines at Midas, Fire Creek and Round Mountain. Most of these deposits,
originally mined as high-grade “bonanza type” veins during the late 1800’s and
early 1900’s were largely ignored by many exploration geologists as
“insignificant, small veins” during subsequent exploration cycles. Currently
operating deposits with similar histories include the Round Mountain mine,
Midas (Ken Snyder) mine, Hollister, Fire Creek and Denton Rawhide. The now idle
operations at Aurora, Borealis, Olinghouse, Comstock Lode and Bodie, California
share similar discovery and development histories.
At the property scale, structure includes Tertiary NW striking, right lateral strike slip and right oblique slip faults related to the Walker Lane Trend with sub-parallel fracture cleavage and coeval sinusoidal, NS and NE striking first and second order extensional “en echelon” or “gash” faults. Large EW to NE trending right oblique (dextral) strike slip faults related to the Pancake Range Lineament transect the property with little if any apparent offset by, or of structures related to the Walker Lane and are probably coeval.
Intense folding is evident
everywhere in the carbonate sediments of the upper Luning Formation. It is
likely that unrecognized overturned folds are present within the sedimentary
package and potentially provide important controls for localization of
mineralization in these sediments.”
There is a potential theory, that
the Pamlico Ridge is sitting on the edge of a once active caldera or at the
very least a highly active epithermal system formed by magma reservoirs which
were once part of the Western Nevada Caldera Complex. After reviewing the local
mining operations, being on site and reviewing geological and topographical
maps of the area we are inclined to believe that there may be more to this
theory.
When a Caldera forming event occurs, the magnitude of the explosion from the volcano is so large that it collapses into itself and after reviewing satellite photos that encompass Pamlico Ridge, you will notice that it has a circular shape with a depressed center. This could potentially explain some of the folding and some of the near vertical structures that are present at Pamlico ridge and why the property feels like rolling hills versus the mountainous landscape surrounding the Hawthorne Valley.
Circular shape of mountains look to be collapsed in the center
Notice how this mountain complex stands out, especially when
compared to Round Mountain, which seems to
lack any sort of noticeable geological features from satellite imagery. Pamlico
Ridge and Round Mountain are both on the Pancake Range lineament and there is the potential that
the magma reservoir that fuelled the Round Mountain deposit also played a part
in the formation of the Pamlico Ridge deposit.
When we discussed this notion with Mr. Carrington and Mr.
Archer, they both reluctantly replied that there is not enough evidence to
support this yet but they could not rule it out either, given what they have
seen on the property. Admittedly, it would take a lot more information to say
definitively what the driving force of the deposit is, but they both seemed open
to the possibility.
In conclusion, this site visit was very
informative and upon doing our research before and after being on the
property we can confidently say that this is one deposit we will be watching
very closely. The planned IP Surveys and drilling in the Pediment zone will
help to paint the bigger picture on this property and only time and testing
will prove out the theory regarding this property being on a Caldera or driven
by an ancient magma reservoir, but in the interim we are looking forward to
Newrange Gold advancing this project and putting together a proper 43-101.
Newrange gold is a Sponsor of Insidexploration however the thoughts and opinions expressed are the author and do not represent that of the company. The Author does not currently hold a position but has bought and sold on several occasions and will do so without warning.
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