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Monday, November 28, 2011

Gold Occurrences in Guatemala

Coat of Arms

Guatemala is the northern most country in Central America adjoining Mexico on its southern border.  Gold mining has been practiced in Guatemala since before the days of the Spaniards by the Maya Indians, and is still being practiced today.. the country is mounted on the north by Mexico, on the northeast by Belize and on the South by Honduras. The Caribbean Sea lies to the east, and the Pacific Ocean to the West.

Some of the core rocks of Guatemala were laid down around 370 million years ago that have since been overlaid by tertiary volcanism many of these mountains contain iron, copper, lead, zinc and traces pf gold and silver that are still being mined today.  The Tertiary period when dinosaurs roamed the Earth was when this massive layer of volcanic rocks were laid down with their accompanying mineral deposits.  The eruptions did not stop during the Tertiary there are volcanoes still erupting today in Guatemala

Volcan Flores one of the many volcanoes of Guatemala
Photo by Rick Wunderman (Smithsonian Museum)

As recently as 23,000 years a very large eruption occurred for me a call barrel that is now occupied by Lake Atitlan in the Guatemalan highlands.  One recent eruption of Mt. Santa Maria in 1902 was one of the most violent eruptions of the 20th Century.  As recently en eruption of the volcano Pacaya in September 2010 caused 1,800 people to flee their homes as the volcano spewed ash, lava and rocks over the surrounding countryside.  The eruption was also blamed for at least three deaths.

It is a well known fact that gold is often found in the vicinity of former volcanic eruption's in deposit great amounts of gold by the action of hot water. Even today there are many hot springs to be found in Guatemala in it which could still be bearing gold laden waters. An especially good place to look for gold is around ancient volcanoes especially those that have created calderas. Gold is not usually found in the center of a caldera but rather at its edges. Many times these gold deposit a company magnetic highs that are found at the outer edges of a caldera eruption.

A great deal of Guatemala is covered by tropical rain forest combined with the rugged terrain and it's prospecting in the country very difficult although not impossible. This condition prevails through all of Central America. In Guatemala there are both placer and lode deposits of gold.  Gold can be found in most of the rivers and streams flowing down from the highlands of the country. Because of ground cover finding lode gold is more difficult although not impossible if you use modern geophysical instruments.

Gold is often accompanied by deposit so magnetite that is sensitive to a flux gate magnetometer. There are other advanced methods of exploring for gold including one very accurate means that involves taking soil samples, and subjecting the samples to analysis by an atomic absorption spectrometer.

It is possible that the area encompassed by Central America could well prove to be one of the most mineral rich areas in the world. 

Saturday, November 26, 2011

Gold Occurrences in Honduras

Coat of Arms for Honduras. Note the crossed hammers and chisels along with the mine entrances in the lower left corner.

Honduras is the largest and most rugged country in Central America. It was little explored until the 1960s because of the dense jungle, steep slopes and deep ravines.  Lack of roads was another contributing factor to the lack of exploration. Volcanic activity is another.  Volcanism is a rather recent occurrence in Honduras like the other countries of Central America having started as recently as 11 million years ago and still continues today.  It is this volcanic activity that carried gold and other polymetallic ore deposits in its wake.

As part of the volcanic arc of Central America, Honduras contains many volcanoes both active and extinct; it is this volcanic activity that brought with it the deposits of gold and other minerals that are found here today.  The area including Honduras has undergone a considerable amount of activity associated with subduction zones that were building volcanic arcs Honduras was part of one of several island arcs originally.  The country was finally accreted to southern Mexico, but there was still a gap between North and South America.  This gap was only closed within the past five million years when Panama was formed allowing a land bridge between the Americas.

Gold isn't the only thing found in Honduras this precious opal came from the Gracis O Dios mine there.
Photo by Rob Lavinsky

Although the situation has improved Honduras to this day is largely unexplored presenting plenty of opportunities for exploration for gold that is present on both placer and lode deposits. There are several gold mines in Honduras where mining is mainly carried out by foreign interests that principally use the heap leaching process with cyanide.  The nature of the mines also lowers the water table.  Cyanide can be neutralized with a solution of laundry bleach or Clorox. 

In some cases whole villages were relocated to new sites that although they provided housing for the inhabitants they failed to provide plots of land where crops could be raised or animals pastured. The findings of an investigatory group were published in the paper, “The Price of Gold: Gold Mining and Human Rights Violations in Honduras.”  The result was made by presenting the Honduran Government with the needs of improving the regulatory needs as pertained to gold mining.

Due to its mainly volcanic origin there is plenty of gold in Honduras waiting to be discovered because although exploration conditions improved during the 1960s there is still plenty of territory that hasn’t been explored yet.  Gold is still there for the taking!

Tuesday, November 22, 2011

Gold Occurrences in Greenland

Greenland suffers from a split personality because geologically it is part of North America, but politically it is part of Europe; to be specific Denmark. Greenland geologically is part of the Canadian Shield although in many places it has been reworked. In the southwest corner is found some of the oldest rock on earth is taking the form of gneiss that has been intruded by a younger magma that provided the radiometric date. It is this younger magma from which a date of about 4 billion years ago has been derived. The gneiss itself is much older.

Like the rest of the Canadian Shield, Greenland is blessed with greenstone belts that are always associated with gold.  The east coast of Greenland lies just to the west of the IapetusSuture Zone making it similar to western Connecticut and Eastern New YorkNorthern Ireland, Scotland and the Scandinavian Peninsula split off the eastern coast of Greenland during the period when the Atlantic Ocean was opening making a strip along the east coast similar to the eastern United States.  Some of the rocks in Scotland are identical to the Catskill Mountains in New York composed of what is called the Old Red Sandstone in Scotland.

A geological team at work in Greenland
Photo by Erik

Although much of Greenland hasn’t been explored as it is covered with up to two miles of ice enough has been explored so there are some active gold mines found on the Island.  The island could become the next mining frontier an idea that drew over 150 people to a meeting about the potential for mineral exploration in Greenland in TorontoGreenland itself is one indication about how the soaring prices for metals attracts miners to the out-of-the-way places that under usual conditions are normally overlooked.  Greenland is an extension of the Canadian Shield that contains many potential mineral deposits.  Just one deposit of cryolite sparked the whole aluminum industry during the late 19th Century.

Greenland underwent two episodes of the breakup of a continent as recently as the Eocene about 40 million years ago and displays both extensional terrain and extensive volcanism just the place to look for gold.  Right across the middle of the island there are extensive flows of lava that cover the surface of the land beneath the ice.  One of these breakups formed the Davis Channel between Greenland and Canada the other involved the formation of the Atlantic Ocean that gave birth to Ireland, Scotland and Scandinavia.  The ancient suture zone was just off the coast of present day Greenland.

Gold isn’t the only precious commodity found on Greenland; True North Gems has also found extensive deposits of rubies in southwestern Greenland.  There are also many other things then gold that are being mined on the island right now.  Exploration is ongoing for other commodities.  One of these is diamonds, although none have been discovered yet geologically there is no reason why they haven’t, and plenty of reasons why they should.

Although Greenland is off the beaten path it isn’t so far away that it can’t be in what is called in international trade a part of the Hudson – Rhine Axis of Trade.

Sunday, November 20, 2011

Gold Occurrences in Mexico

The Coat of Arms of Mexico

There is an old Mexican saying that it takes a silver mine to make a gold mine.  Mexico is blessed with an abundance of both metals.  My first introduction to Mexican gold was when a group of us tried to acquire the San Pedro Mine in San Luis de Potasi.  We couldn’t make a deal for this mine that had been worked since the time of the Aztecs, but it still contained around 12 million tons of low grade ore similar to that of the Carlin Trend in Nevada

Mexico is within the Cordilleras that go all the way from northern Alaska to Tierra del Fuego in southern Argentina.  Throughout these mountains there are abundant mineral deposits some of them have been worked since before the Americas were discovered by Columbus in 1492.  Exploration is still ongoing throughout the Cordilleras to this day with many gold and silver mines being developed.

The best description of mineral occurrences in Mexico including gold is that Mexico is a virtual treasure chest with an abundance of minerals hardly surpassed anywhere on earth.  Some of the mines in Mexico have been continuously worked for over 500 years.  In one place there is virtually a mountain of silver that has been worked since the days of the Aztecs or before.  In another place the workers in a mine stumbled upon a cavity in the rock where they discovered selenite crystals the size of tree trunks.  It is so hot in this cavity you have to wear air conditioned suits to enter.

Poughkite an ore of gold and selenium from the Monctzuma Mine in Mexico
Photo by Rob Lavinsky

There are two mountain ranges running for most of the length of the country named the Sierra Madre Oriental and Occidental with the Valley of Mexico between them.  In many places these mountains are volcanic in nature with the minerals found in them coming from the volcanism.

Lode deposits of gold and bedrock deposits of other minerals are abundant in Mexico, but that is not all.  Throughout Mexico there are many placer deposits of gold found in most of the rivers and streams, and because of the lack of glaciation there are also saprolitic deposits where the bedrock has been turned into clay leaving the lode deposits of gold and quartz behind in place waiting to be mined.

Many mining companies are actively exploring for more gold deposits in Mexico throughout the country, but there are also mines like the San Pedro Mine that has been worked since the days of the Aztecs.  The potential for finding gold and other valuable mineral deposits in Mexico remains very high.

Thursday, November 17, 2011

Gold Occurrences in Nunavut

Nunavut is shown in red.

Eastern Nunavut is dominated by the mountains of the Arctic Cordillera a range of volcanic mountains that extends southwards from Ellsmere Island to the Torngat Mountains of northern Labrador and Quebec.  At 8,583 feet (2.616 meters) Barbeau Peak is considered to be the highest point on the east coast of North America.  Many of these mountains are of volcanic origin, and some of them still display cones.  It is the inhospitable nature of the Canadian Archipelago combined with the volcanic nature of these mountains that we must assume there is plenty of gold that hasn’t been discovered yet.

In essence the Arctic Cordillera are reworked rocks of the Canadian Shield and in many respects are similar to the Appalachians although the orogeny that formed them is much younger.  The area is fairly heavily intruded with volcanics that are associated with the orogeny.  To the west of these mountains Nunavut is composed of older rocks belonging to the Canadian Shield.  There are a series of greenstone belts that are found throughout the Canadian Shield including those found in Nunavut.  It is in these rocks that much of the gold in Canada has been found.

The Meadowbank Gold Mine under construction.
Photo by Agrico-Eagle Mining

Nunavut’s first gold mine opened in 2010 operated by Agnico-Eagle it is the first gold mine in the Territory and the first gold mine to become operational here.  The mine is called the Meadowlake Mine that opened in June 2010.  Exploration for other mines is proceeding.  There have been plenty of problems this mine has faced ranging from difficulty in off-loading freighters, leaky dikes, getting permits and delays in completing an airport capable of handling jets.  With these problems it has been estimated that production at this mine is apt to be more then CN$350 per ounce.

At one time in 1999 there were two operational mines in Nunavut both of these mines produced lead-zinc.  One of these mines had the title of being the most northerly mine in the world.  This was the Polaris Mine on Little Churchill Island.  The Nanisivik near the village of the same name produced silver along with the production of lead-zinc.  Both mines are now closed.

There is an active exploration industry and several other mines are in the process of being opened.  Prospecting in Nunavut is expensive but there are grants made available from the territory of $8,000 if you are a serious prospector. The territory also conducts classes for the local population in a program that travels from community to another conducting night and field classes for the people living there. These classes have been conducted for several years, and it was a local prospector who took the classes that found a deposit of gemstones in 2001 that he sold to a mining company.
Mt Aasgard in Nunavut is one example of the terrain you will encounter.  It is located on Baffin Island

Unlike other parts of Canada, Nunavut has not been well mapped so there is plenty of opportunity for prospectors to find valuable mineral deposits. One of the things that you have to be careful of is that it takes about 100 prospects before you can develop a single mine. 

Tuesday, November 15, 2011

Gold Occurrences in the Northwest Territory of Canada

The NWT of Canada

Some of the oldest rocks on Earth are the Acasta Gneiss found in the Northwest Territory of Canada.  The rock itself is metamorphosed sedimentary rock that is far older then its radiometric date of 3.8 billion years.  A zircon found in this rock has been dated as 4.03 billion years old.  These rocks of the Acasta formation are by far the oldest rocks discovered in North America, and were originally laid down in the Hadean era.

A fragment of the Acasta Gneiss on display in the Natural History Museum in Vienna.
Photo by Pedro Alexandrade

Unlike the Yukon that lies to the west of the NWT that has no exposed rock of the Canadian Shield most of the territory is composed of rocks of the shield.  These rocks display plenty of greenstone belts notably the Yellowknife Greenstone Belt near Great Slave Lake.

Gold was discovered in the territory in 1898, but active mining did not commence until the mid 1930s in the area around Yellowknife. The opportunities for additional exploration and prospecting in the territory abound. There are other valuable mineral deposits that are being worked in the territory including uranium and the recent discoveries of diamonds have resulted from the opening of diamond mines.

Yellowknife, NWT in the mid 20th century.
Photo by YK Times

A vast amount of information is available through the Northwest Territory’s Geoscience Office in Yellowknife. Another source of information is the Prospectors and Developers Association of Canada (PDAC) in Toronto, Ontario. The Northern Miner in Toronto is a weekly newspaper covering the mining industry worldwide including the Northwest Territory.

Prospecting for Gold the Northwest Territories of Canada along with many other valuable minerals including copper, diamonds and uranium is a viable occupation. Parts of the territory along the Arctic coast and on the islands in the Arctic Ocean contain gas and oil. A few years ago a geologist inadvertently published the locations of test wells on Ellsmere Island and received a proper wigging for his efforts. The territory depends on mining for most of its economy. Today however the emphasis is on diamonds rather then gold.

A significant gold discovery has recently been announced at the REN gold site. The gold was discovered in a seven kilometer long iron formation. Gold is often associated with iron especially with the ore granular magnetite. Some of the grab samples of ore collected have as much as 198 g/t of gold. In follow-up drilling more gold was found in the host rocks adjacent to the gold rich body of iron ore.  The area around Yellowknife is dominated by the Yellowknife Greenstone Belt that has been the scene of several past and present gold mines.

Over the years there have been a number of gold mines found in the area around Yellowknife the territory’s capitol. This city was originally settled as a gold camp and became the capitol later. The diamond mining industry is now centered Yellowknife although the actual mines are located to the Northeast of the city around the Lac de Gras area.

Sunday, November 13, 2011

Gold Occurrences in the Yukon Territory

The Tintina Gold Belt goes from northern British Columbia to Alaska for 1,200 kilometers.   USGS

You could say it all began with the Klondike Gold Rush in 1898, but the history of gold in the Yukon goes back to the early traders and trappers who first found gold in the territory.  Much of this gold was in placer deposits. Placer is a Spanish word meaning a place where gold was dug from the earth mainly from sand & gravel deposits where the gold was concentrated.

The southwest corner of the Yukon is within the Tintina Gold Belt a great arc that extends from northern British Columbia throughout the Yukon and ends in the Pacific Ocean just above Anchorage, Alaska.  The Tintina is about 1,200 kilometers long and 200 kilometers wide.  Many of the earliest gold discoveries in the Yukon were placer deposits, and even today large quantities of placer gold are produced. During the Klondike Gold Rush many of the miners passed through the Yukon on their way to the gold fields of the Klondike in Alaska without ever sampling the area in the Yukon through which they passed.  If they had the gold rush might just as well been called the “Yukon Gold Rush.”

This part of North America escaped the extensive bouts of continental glaciation that covered much of the northern hemisphere for the past million years allowing the placer deposits that had formed for millions of years to remain in place; the placers were destroyed by the glaciers in other parts of northern north America.  When the glaciers came a good part of the Yukon was part of Baringia an arid land that joined Asia to North America when the sea level was four hundred feet lower then it is now.

For many years geologists and prospectors thought the gold in the Yukon was all placer gold eroded from formations of rock that no longer existed, but in recent years a number of hard rock mines have been put into production.  Many of these lode gold mines are associated with the mineral scheelite, an ore of tungsten in the form of calcium tungstate.  One hard rock mine is actually called the Scheelite Dome Mine (VSE:LAO) because of the amount of scheelite it produces.

The Yukon Territories are shown in red.

Most of the river systems in the Yukon produce placer gold, and lode gold can be found related to intrusions of magma into the country rock.  There are plenty of placer operations found in the territory, and an increasing awareness of the lode gold potential of the Yukon.

Gold Panning in Bonanza Creek in the Yukon.
Photo by Janothird

Friday, November 11, 2011

The Benefits of prospecting during Cold Weather

A snowy owl in flight during cold weather, one of the best times for prospecting.

The greatest benefit of prospecting during cold weather is there aren't any black flies around to gnaw on your bones. There are also many other benefits, probably the second most important is there aren't any mosquitoes around either. These two critters can make prospecting during the warmer month’s sheer hell. Another critter that is missing during the cold months is snakes. Many snakes are harmless, but the onesyou are apt to encounter while prospecting may not all be. It is the venomous snakes like copperheads, coral snakes, cottonmouths and rattlesnakes that can raise hob within any prospecting expedition.  For the most part even bears go into hibernation during the coldest months of the year. 

That leaves some other critters that might remotely be a bother, but only members of the deer family and the mountain lion are truly dangerous.  Usually deer try to avoid contact with humans, but during rutting season in the late fall male deer have been known to attack humans.  I once had a late fall encounter with a bull moose, a member of the deer family that could have been dangerous, but the moose didn’t like the smell of my companion that I’d been after for two weeks to take a bath.  The other dangerous animal is the mountain lion; they look upon humans as lunch.  Most mountain lions are confined to really wild areas in the western United States or the Florida Everglades.  They are very rare, but I observed one in Connecticut about thirty years ago.  According to the Department of Environmental Protection in Connecticut there weren’t any mountain lions in the state.  This spring one was killed on the Merritt Parkway, and another was observed by a canine control officer in northern Connecticut.

The perfect thing to go prospecting in during the winter.  Vehicles like this are used extensively for prospecting in Canada and other cold places.  This is a prototype that was built in Montana during the 1970s.
Photo by Gyre

The greatest benefit of cold weather prospecting is you can see so much further when the trees are bare.  One of the greatest problems facing a prospector is being able to find bedrock.  No leaves or other vegetation make it so much easier.  If you are panning for gold in a stream you can still do so just by wearing rubber gloves.  When I was prospecting in the cold weather I used to wear the bright red gloves that were covered with rubber, and were insulated.  They kept the cold water out, and the heat in.

It’s also much easier to get around in the bush or muskeg when the ground is frozen; in fact in some places where you want to prospect can only be approached during cold weather.  You don’t want to get into muskeg during warm weather, you’ll still be there.

Even if you are not out prospecting it is still a good time to plan your next expedition by studying the literature about the area where you intend prospecting, and laying your plans.  Remember there are plenty of other minerals worth looking for besides gold.

Thursday, November 10, 2011

Gold Occurrences in British Columbia

It is near Mt. Robeson where the Fraser River rises that was the scene of a gold rush in 1859.   Tobi87

It was in Yale, British Columbia on the banks of the Fraser River where I first learned about British Columbia gold there were several flour sized flakes gold in the bottom of my gold pan. From what I understand this flour sized gold is characteristic of the Fraser River. For the benefit of the reading audience it takes approximately 40,000 of these to weigh a troy ounce (31.1 g).  At the time there was a terrific thunder shower coming up, and I worked the pan out in about two minutes leaving the proprietor of the gold panning site completely mystified because he had already seen the Connecticut greenhorn could work so fast, he already seen the plates on my car.  He didn't know I had been a prospector most of my life. The Fraser River was the site of a gold rush in 1859, and there is still gold to be found in the Fraser River system.  There are also jade boulders found with the gold in the river.

Yale, British Columbia during the Freaser River Gold Rush in 1859

British Columbia also contains the southern terminus of the Tintina Gold Belt in the northern part of the province. This appears to be the largest gold belt in the world since it is traceable all the way from northern British Columbia, through the southwest corner of the Yukon Territory and sweeping all the way across Alaska for a distance of 1200 km where it finally ends in the Pacific Ocean just above Anchorage, Alaska.

The first discovery of gold by Whiteman was at Gold Harbor on the west coast of Moresby Island near the Haida village of Tasa in 1850 where it was discovered on Mitchell Inlet, an arm of Gold Harbor.  This discovery touched off a brief gold rush in 1851.  This led to the area being declared the Colony of the Queen Charlotte Islands.  The British government didn’t want the islands to be overrun by American Miners even though the gold deposits proved to be superficial in nature, and there are stories about the American miners being harassed by the local Haida warriors.  Later the area became the site of a modern mine for iron rather then gold.

Like all the beaches in the Pacific Northwest of the United States and Canada The beaches do contain flour gold in payable amounts sometimes covering the beaches with enough gold so they attract the locals trying to get as much of this gold as possible before the next tide washes it away until the next big storm that may wash up enough gold to be noticeable again.  In the same area the mountains of the coastal range including the British Columbia Batholith have had several producing gold mines and numerous showings of gold.

There is another gold producing area on the western slopes of the Rockies and the rivers and streams draining them.  This area was made famous during the Fraser River Gold Rush and the later Caribou Gold Rush. 

Gold is not the only source of mineral wealth in the province because it also contains world class deposits of jade that are mined both in-situ and as boulders of jade found in numerous rivers.  The area around Cache Creek has produced both gold and jade.  British Columbia is also noted for producing large quantities of copper, lead and silver.

British Columbia has vast deposits of mineral wealth throughout its length and breadth with many deposits yet to be discovered.  There are numerous mines that are accessible only by air especially in the northern part of the province.

Tuesday, November 8, 2011

Gold Occurrences in Alberta

Gold country in Alberta

Although there are over 200 reported instances of lode gold occurring in Alberta there are several places where it might be found.  In the very northeast corner of Alberta is a small fragment of the Canadian Shield that might contain the right geology for the occurrence of gold.  North of the 55 degree line is a mass of Paleozoic and Mesozoic sediments that have been intruded with volcanics, and are highly faulted and sheared from earth movements.  These sediments are quite apt to contain gold.  Another place where gold is apt to be found is in the tailings of the Athabasca Oil Sands.

The area underlain by the Precambrian rocks in northeastern Alberta has more then 200 known occurrences of gold.  Some of these deposits produce the potential into being developed into significant mines.  These deposits are mainly in sulfide hosted deposits with the gold being associated with other metals.  Many of these deposits are found in hydrothermal veins associated with iron mineralization.  Many of these deposits especially those found in the Athbasca basin were emplaced within the past 1.5 billion years.  Many of these deposits are in Phanarozoic deposits especially those whose host rock is in black organic rich shale.  Many of these deposits are to be found in the Alberta portion of the Rocky Mountains.  There are many places where by sampling the soil it is possible to find anomalously high concentrations of gold.  These anomalies indicate the possible presence of viable gold deposits lurking underground.

The Athabasca Tar Sands a possible source of placer gold.

Placer deposits in the province are found in rocks ranging from the Cretaceous to modern.  A good place to look is in conglomerate, or in stream gravel.  Deposits of fine placer gold are found along the Saskatchewan River as it flows through Edmonton.  On warm lunch hours one can see executives with their pants rolled up panning for gold.

This kind of gold is usually found in fine particles that are known as flour gold.  The color of this gold ranging from the pale yellow to a coppery red depending upon what other metals are alloyed with the gold.  The yellowish specks of gold are alloyed with silver forming a compound called electrum. The reddish colored gold is alloyed with copper. Sometimes the gold that is discovered and placer deposits is coated with iron or manganese oxides that have to be removed with acid. Gold itself is not affected by any acid except act the region a mixture of nitric and hydrochloric acids. Fools gold differs from real gold because it is brittle and crushes easily.

There are several different river systems in the province that do contain placer gold among them are the North Saskatchewan, Red Deer, McLeod, Athabasca, and the peace River systems.