Gold, Mining and Prospecting

The Miller Process for Refining Gold

2012-02-09T13:09:00.000-08:00

Gold Bars Agnico-Eagle

Ever wonder how most gold is refined? No for the most part they don’t use the Wolhwill Process rather they use the Miller Process. Unlike the Wolhwill Process described earlier in this series the Miller Process doesn’t use electricity but rather uses a stream of chlorine gas that is passed through a crucible of molten gold that produces gold that is 99.95 Fine. It works to remove all the impurities because gold is least affected by chlorine so all the other impurities are removed as chloride slag floating on the surface of the molten gold where it is skimmed off.

In this process the dore bar is melted in an induction furnace where the chlorine gas is introduced into the molten metal by a rotating lance. The lance is controlled in a very precise manner in a way there is no break through of the chlorine gas to the surface of the molten metal. This removes what are termed “By-metals” like silver, copper, nickel along with any other metals. The process also removes amphoteric elements like sulfur, selenium, tellurium, arsenic and bismuth. These elements are all removed from the molten metal as chloride slag that floats to the surface of the charge where they are skimmed off for further treatment.

The process takes from 2 to 4 hours to complete with the chloride fumes being removed and filtered by a two stage wet filter or a two stage dry scrubbing system that maximizes the recovery of the chloride as well as the cleaning of the exhaust air from the process. In the process slag is poured off the top of the melt into a crucible and allowed to slowly cool so any gold that has been caught up with the chlorides will settle to the bottom where it can be recovered as a button of gold when the crucible has cooled completely; it is then added to the remaining molten gold. In this process the particles of gold remaining in the crucible are carefully removed by hand as well as the separation molds when they have cooled.

Once the gold has cooled it is poured through a ceramic filter directly into the granulation equipment or anode molds if the Wolhwill process is used to further refine the gold.

The main advantages of this process are its quick turnaround time, size of the charge that can be from 20 kg to as large as you like. The rotating lances are made from temperature resisting ceramics for long life and evenly introduce chlorine to the melt. The use of modern induction furnaces keep the consumption low using far less kilowatts then coil type furnaces for the same size of melted product.

In this process the gold produced is 99.95 Fine that is good enough for most commercial purposes. Most of the metals remaining in the gold are mostly silver and copper that if desired can be removed using the Wolhwill Process producing gold bullion that is 99.999 Fine.

The Foundations of a Good Gold Mining Business

2012-02-09T11:06:00.000-08:00

The type of mine where good business practices are used.
Photo by Greverod

For small operations, mining for this precious metal takes a lot of personal sacrifice and faith. Recently,
reality television shows like Discovery Channel’s “Gold Rush” and “Bering Sea Gold” have brought the
business of gold mining to the general public’s attention. Television shows like these do try to show all
sides of the business, but as with all television, the glamorous side seems to come out more than the
gritty side.

At the heart of every good gold mining operation are a few basic yet necessary requirements. These
requirements provide the foundation for a legal and well-planned gold mining business. Before you go
prospecting for gold, you must be sure to take care of the following…

Locate a mining claim: In accordance with the Mining Law of 1872, a mining claim can only
be staked on federally-administered lands that have not been previously claimed or closed to
mineral entry under some special act, regulation or public land order. There are 19 states where
mining claims can be located.
Stake your claim: Federal law requires that claim boundaries be clearly marked. Most states also
have additional staking requirements.
Record the mining claim: In accordance with the Federal Land Policy and Management Act of
1976, all claims and sites must be recorded with both the state and the proper Bureau of Land
Management (BLM) office.
Secure an investor or investors: The total amount of money needed to run a successful mining
operation will depend on the size and location of your claim, the number of employees hired
and the method of mining used. Typically, a company will bring in managers with prospecting
experience to assess the claim and decide on an operating budget. This is the amount proposed
to investors. Investors will require a return on their initial investment, and smart prospectors
will hire an attorney to ensure the mining company receives a fair deal.
Purchase the right equipment: Investing in the right prospecting tools is essential for success.
When you use the right equipment, you find more gold and make more money.
Hire experience: For the most part, you want your employees to have previous experience in the
specific job they will be performing. This reduces the time and money used for training.
Meet all federal and state mining safety and labor law requirements: There are laws and policies
that must be followed in order to continue operation. Each state has its own safety training
policy, so check them out before opening the operation.
Maintain workers’ compensation insurance: Even with proper training, accidents can happen.
Protect your company by maintaining the right workers’ compensation insurance. In some
states, it is actually a law to maintain workers’ compensation insurance, so check your state’s
requirements before hiring.
Maintain the mining claim: Under the federal mining law, all claims must follow the annual
mining claim maintenance requirements and pay an annual maintenance fee.

In addition to these practices, all gold mining operations should hire an accountant and office manager
to maintain all financial, employee and other records. A good operation keeps great records and a close
eye on profits and losses.

For more information on federal mining laws, visit the U.S. Department of the Interior Bureau of Land
Management website and search “gold mining.”

About the Author: Allison Lane owns the website MPA Programs and enjoys writing guest blog posts on various topics of interest.

Refining Gold using Electrochemical Processes

2012-02-06T18:18:00.000-08:00

An electrolytic cell used in the commercial refining of gold using the electro-chemical process.

This is a continuation of the previous article about the recovery of gold from concentrated stream heavies. In this article we will examine the WolhwillProcess that was originally invented in 1874 and is still in use today. This process is used to produce gold that is 99.999% pure. As an industrial-scale technique the Wohlwill process that was invented by Emil Wohlwill for refining gold using methods developed for electrochemistry.

The process makes use of a bar cast from impure gold that has been separated from concentrate like that in the first part of the process we explained in an earlier article. This is done by pouring the gold and other metals into a crucible, melting then and pouring them into a mold producing what is called a “dore” bar composed of gold, silver and PGM. If the amount of gold present in the dore bar is less then 95% it will be necessary to add enough pure gold to bring its content up to that level otherwise the other metals will be carried over in the finished product making the gold less then 99.999 fine. The Dore bar acts as an anode in the process.

The cathode in this reaction is made from thin sheets of 24k gold that are spaced on each side of the Dore bar that acts as the anode. Providing the anode is composed of more then 95% gold the remaining metals in the cathode will be deposited in the bottom of the electrolytical cell as anode sludge that can be recovered and the values of silver and PGM recovered in a later process.

The gold along with the other metals are dissolved at the anode when current is delivered to the cell with pure gold coming through the chloauric from ion transfer where it is plated as pure gold at the cathode. After the anode is completely dissolved the cathode is removed and melted down or processed for making the end product that is usually gold bullion pure gold like this is too soft for most other uses.

At 99.999 fine this gold is too soft for most purposes other then bullion so it must be alloyed with other metals most commonly silver although in some cases copper is also used. For making jewelry the most common karats used are 14 and 18 k. This is done by remelting the bullion and forming it into the shapes desired.

There are plenty of gold refiners that will refine the concentrate into pure gold, but they often keep the platinum values as part of the refining fee.

Cleaning up Concentrates containing Gold and Platinum

2012-02-01T17:53:00.000-08:00

Hematite particles forming ferro-fluid with a rare earth magnet beneath a sheet of glass.

One of the problems in the recovery of gold,silver and platinum from concentrates of stream heavies is the removal of iron oxides that make up the majority of heavies. Most of the other heavies are composed of silicates and in rare cases oxides of various elements. In the case of iron oxide there are two types present in most heavies. The most easily removed is magnetite because it is attracted to an ordinary magnet with the best being an Alnico magnet. This will quickly remove the magnetite that is the easiest to remove. Hematite is the second iron oxide in heavies that is not attracted to an ordinary magnet, but is attracted to a rare earth magnet that can be ordered on the internet. The remaining heavies composed of mineral silicates and oxides being much less dense and having a far lower specific gravity then gold, silver or platinum that is left behind in the pan.

The iron oxides can be removed in two stages; the first is removing magnetite. There are commercial magnetic separators available, but for the small amount usually encountered an ordinary magnet will suffice. A small amount of concentrate that has been thoroughly dried is placed on a sheet of paper and the magnet is passed over the concentrate just above its surface, but high enough not to touch the concentrate. The magnetite present will stick to the magnet so you will have to periodically remove it from the magnet.

The hematite is removed in the second step by using a small rare earth magnet by repeating step 1 using the more powerful magnet the remaining concentrate containing heavies, gold, silver and platinum group metals. This concentrate is poured into a separate container for further work in the process.

Although geologists know ways of separating heavies using dense fluids, but they are all highly toxic and shouldn’t be used by an untrained layman. The best way to remove them is with a small ten inch gold pan immersed in water using conventional panning methods. Its tedious work, but the pan full of concentrate can be worked down until the only thing left in the pan is gold, silver and platinum group metals (PGM).

The remainder in the pan is gold, silver and PGMs that are saved for further processing; because of the length of the whole process we are going to divide it into several articles we will publish in the near future. Watch for them!

Gold Occurrences in Colombia

2012-01-24T08:52:00.000-08:00

Plate tectonics found in Colombia.

It doesn’t happen very often, but

Colombia

was the subject of a whole section in Engineering and Mining Journal (E&MJ) all about the boom in minerals there. Colombia is the northern terminus of the Andes Mountains that is also one of the last areas in the Andes to be explored for minerals. Even the author is interested in the goings on in Colombia because his friend Nick is developing a mine that is located between the Pig Pen and the Old Man in the northern Andes. We have been consulting on this mine for the past year and although it is beyond the range of the internet Nick gives us regular reports on his progress whenever he gets into town.

Colombia has three different distinct areas where gold is found. One of these areas is in the Andes proper where it is found as epithermal deposits in shear zones. The area also contains placer gold. The second area is in the Sierra Nevada de Santa Marta Mountains in the northeast of Colombia. These mountains are not part of the Andes, but rather are a distinct mountain range in their own right that has the distinction of being the highest coastal range in the world at 5,700 meters (17,760 feet). Although these mountains are reported to contain much gold it is protected by a tribe of Indians that were never conquered by the Spaniards that take a dim view of gold seekers that are after their gold. The third area is in the Guyana Shield a large group of Precambrian Rocks that are found in the southeastern part of the country where they continue into Brazil, Guyana and Venezuela.

E&MJ considers Colombia as the last frontier of the Andes Mountains because so much has already been discovered in the Andes further south. Gold is the least of the mineral wealth of Colombia the country is already the home of the largest deposits of emeralds on earth with finds dating back to the days of the Incas. Colombia also contains coal measures that are largely being exported to Europe. One company Xstrata produces high grade coal from its Cerrejon mine the largest in Colombia.

Getting back to my friend Nick in his prospecting he has discovered a pegmatite in the part of Colombia where he is prospecting that contains crystals of aquamarine of euclase, This will show you that much more then gold can be found in Colombia.

Gold Occurrences in South America

2012-01-20T21:13:00.000-08:00

Precambrian Cratons of South America

From the Isthmus of Panama to Drake’s Passage South America is a veritable treasure house of minerals including gold. Found on this continent are some of the great mineral deposits found on earth. Of all the deposits of minerals the first discovered by modern man was gold when the Incas filled a room with gold ornaments to ransom their Emperor from the Spanish conquistador Pizzaro and his men. Even with this vast treasure their efforts were ignored when their Emperor, Athapulco was executed by the Spaniards.

There are several different gold provinces in South America with the largest being the Andes Mountains reaching from the Panama border to Cape Horn on the island of Tierra del Fuego. The Sierra Nevada de Santa Marta Mountains are found on the northeast coast of Colombia, the highest point on the Atlantic Ocean at 5,800 meters (19,278 feet) reportedly contain vast amounts of gold that is guarded by the only Native Tribe that wasn’t conquered by the Spaniards; these Indians to not take kindly to gold seekers even today. It is thought the Sierra Nevada’s are a high volcanic island that was plastered to South America by earth movements in the past.

In eastern South America there are several Precambrian cratons that also are known gold bearers. These cratons are the Guyana Shield and the South American Platform that in many places are covered by younger sediments. Many of the sedimentary basins contain gold that was washed down from the mountains or the Precambrian shields as placer gold.

Like other areas that produce gold in the world the deposits are associated with volcanism or regional heat sources whether ancient or recent. A great deal of the gold found in South America is concentrated along the chain of the Andes Mountains. More gold is found in the Precambrian cratons of eastern South America. A separate source of gold is found in the Sierra Nevada de Santa Marta Mountains in northeastern Colombia.

One of the hot spots in the Andes is the northern end of the chain in Colombia where there are several mining companies staking claims or already have active gold mines. It is in the northern Andes where the author has dibs on a gold mine that is just opening.

Gold is found throughout South America that has already been the home of several historical gold rushes. From appearances there is a great deal more gold that hasn't been found in South America.

Gold Occurrences in Central America

2012-01-15T13:58:00.000-08:00

Map of Central America

With the exception of Belize gold is found throughout Central America to the extent that the area has become a Mecca for gold seekers. The big attraction is the chain of volcanoes that reaches from one end to the other going north to south. Central America is also one of the youngest landmasses on Earth that hardly exceeds 5 million years old. The lode gold deposits are all epithermal deposits in nature where the gold is deposited in concentric rings around the volcanoes in the many shear zones in the area.

Recently the level of gold exploration in Central America has increased because the region is not well explored and one might say it is under explored. At the present time ounce of gold carries a high price tag combined with the laws of all the nations in Central America that for the most part are pro-mining and exploration.

The very formation of Central America as an island arc of volcanic islands that was in filled by sediments from both North and South America would be enough to form gold deposits. Most of the lode deposits found in Central America are epithermal in nature associated with volcanism forming in fault and shear zones. The volcanism is formed by the Cocos Plate being subducted beneath the area west of Central America just offshore.

Several gold mining companies started exploring the area during the late 1990s in the long isthmus that connects the America’s finding the whole of Central America is spotted with high grade gold deposits. Central America may prove to be one of the premier gold bearing areas on earth. Success prospecting Central America will prove to be more successful for those companies that strive for community support among the inhabitants rather then the old time methods of dig and run leaving a mess behind. This will also help them to get exploration permits leading to the development of a mine if it is economically feasible.

Central America is about the size of the Yukon Territory of Canada but contains several countries all of which except one have gold deposits. The one exception is Belize that does not contain any reported gold deposits. Throughout most of the area are mining laes similar to those found in Canada meaning overall they are friendly to the mining community.

Now that the price of gold is hovering around US$1,600.00 per ounce has caused a significant number of grassroots discoveries of gold throughout the region. Central America is a virtual treasure chest of minerals, more then gold is found there. One nation, Panama is estimated to hold the largest copper deposit in the whole world. It is not only a miner’s paradise but one for investors too.

Gold Occurrences in El Salvador

2012-01-10T20:35:00.000-08:00

Coat of Arms of El Salvador

There are several volcanoes located in El Salvador with most of them found in the western part of the country and have all erupted during the Holocene. It takes volcanic activity to create gold deposits, and that is exactly what has happened in El Salvador. The heat from the volcanoes has driven the gold out in concentric circles around the volcanoes and is deposited when the temperature of the water drops below 300^oC to about 200^oC. Quartz is also deposited at about the same range of temperature so they are often deposited at the same time.

Most of the lode gold found in El Salvador and Central America in general are in the form of epithermal deposits associated with the many volcanoes in the region. These volcanoes are products of the subduction zone just off the west coast of Central America. Many of these deposits grade to copper with depth making it possible that the largest copper deposits can also be found in the area.

Although there are little references to placer gold in the country it is reported to be found in most rivers and streams flowing from the interior as placer deposits in the bottom of the valleys. Like other placer deposits it is found associated with the gravel deposits associated with flowing water.

First there was a gold rush in El Salvador that quickly was followed by the lawyers. Although gold in plenty has been found in the country its large scale mining is being opposed by community groups, locals and environmentalists. It seems their concern is mainly the distribution of wealth between the miners and the local population. As we speak this is a battle moving its way through the courts!

Pacific Rim Mining has a project named El Dorado that is 65 km east of the capital of San Salvador that is presently in an advanced stage of exploration indicating there is 1.4 million ounces of proven resources available and a potential of much more that is the target for the present exploration program.

Mining and exploration is governed by the 1996 law that was last amended in 2001.

This law is administered by the Ministry of Economy’s Department of Hydrocarbons and Mines governs the granting of exploration license as well as exploitation concessions. This allows the applicant the right to produce and sell valuable products recovered from natural resources within the area of the concession. An Environmental Impact Study (EIS) has to be approved by the Salvadoran Ministry of Environment and Natural Resources as well as satisfying a number of other conditions. Once it is granted the law requires that mine construction be started within the next twelve months in accordance with the conditions on the final permit.

Closing a gold mine

2012-01-02T21:12:00.000-08:00

An open pit mine.

The formal name for closing a gold mine is mine closure that occurs when the ore extracting activities at the gold mine have ceased, and ushers in the final decommissioning of the mine and its reclamation. This usually entails laying off most of the workers that can have a very significant impact on the community around the mine and the local economy. This is the time that the end of the life of a mine when the majority of reclamation work is completed so as to make the land safe and useful for other purposes again.

In many of the countries where mining activity is prevalent much of the closure planning has not yet been formalized leading to a floor of unintended consequences that have the potential of becoming a sovereign risk if not well managed.

Closure planning is a development in mine closure that continues throughout the life of the mine that usually starts before the mine is ever in production and is an integral part of the mines business plan. The closure plan undergoes periodic updates throughout the time of active mining, and incorporates a final decommissioning plan for the mine. The Australian model for my enclosure is also followed in many other countries with this model being the standard.

Most miners follow a progressive reclamation plants throughout the life of the mine that reduces the reclamation burden on the mine when it is finally closed.

There are two types of mines that require closure one of them is the open pit mine it is usually closed by a special type of explosive round is called a quarry closure shot. This is done by drilling a regular shot pattern only the shot holes are progressively shorter to further from the quarry wall that you get. What you are left with is a graded pattern of shot rock that leaves a slope down from the former quarry walls. This slope is often covered with topsoil and planted.

An underground mine is treated differently where in many cases a large concrete plug about 3 feet thick is placed over the shaft effectively limiting access to the mine. Some underground mines are capped using large metal grates that are usually used on deep level shafts that allows airflow to occur through the deep tunnels that helps prevent subsidence.

Older mines typically used wood beams, a foot or more thick, under loose rock or dirt as caps. Eventually the wood rots and sinkholes might develop. These mines are typically recapped with concrete, steel plates, expanding foam, or a combination.

Steel plates are used primarily on horizontal shafts, but are used on vertical shafts occasionally. Doors are added if access is needed. Holes are cut into the plate to allow for drainage as well as for a bat entrance.

Expanding foam is used mainly with vertical shafts where the use of the shaft is no longer needed. It forms a plug 6 feet or more thick. A 4-to-6-inch (100 to 150 mm) pipe through the plug allows for pressure equalization as well as drainage, or even as a bat entrance.

Closure planning has two different components. On-site planning is mostly about environmental rehabilitation and returning the landform to a reasonable condition. Off-mine closure is about loss of livelihood, which is a more complex issue.^[5] An element of this is generating an offset against the high cost of environmental remediation issues, which in certain cases can exceed the value of the mineral that was mined originally. ^[6]

The Importance of a Business Plan in Gold Mining

2012-01-02T12:29:00.000-08:00

A collection of classical capitals.

One of the most important document in gold mining or exploration, any mining or any business ventures is a good business plan that acts not only as a road map as to how the operations will proceed, but is also necessary to get capital for the operations of the business. Yes, gold mining in this sense is like any other business whether it is selling shoelaces or building rocket ships all business have to have a roadmap to their success.

If you are not familiar with a business plan it is a formal statement of the goals of your business. It also includes the reasons why you believe those goals are achievable and how you expect they can be achieved, and the way you are going to reach these goals. The business plan may also contain information about the personalities that will be conducting the operations necessary to achieve these goals.

A well-written business plan will also target whatever changes that may occur as to how the public perceives the business and its branding by the customer, client, taxpayer or the larger community as a whole. When your operations assume a major change such as the gold turning the copper at depth as often happens. It can be also used for planning new ventures or additional minds. Most principals or investors require a 3 to 5 year business plan since investors will look for their annual return of investment in that length of time.

There is a great deal of information about business plans on the Internet that can be found by Googling the phrase business plan. In addition there are also many, many templates that are available online where literally all you have to do is fill in the blanks and your business plan is written. Using one of these blanks is very helpful, however the best way to write an effective business plan is by scratch. At the very least by Googling business plan you can quickly gather a great deal of information as to how to write one.

No matter whether you use a pre-existing template or start writing your business plan from scratch you will quickly discover how much smoother everything goes for you. The business plan will not only direct you in operating the mine have but also make raising money far easier. There is not any operation on earth that does not benefit from a well written business plan.

Gold Occurrences in Panama

2011-12-29T10:09:00.000-08:00

The Coat of Arms of Panama shows plenty of evidence about the gold mining history of the country.

The Isthmus of Panama is what joins North America to South America, and is the home of the Panama Canal joining the Atlantic and Pacific Oceans. Not surprisingly Panama also contains extensive gold deposits that have only recently been exploited. Although gold was known in the earliest days it wasn’t until the early 1990s that several groups of miners who were mainly Canadians got several concessions from the Panamanian government to exploit the mineral resources of the Republic of Panama. At the time because of lack of infrastructure there was no sense in mining Panama’s mineral wealth. This all changed when terrorists destroyed the World Trade Center in New York City on 9/11/2001 by ramming the buildings with airplanes. This started the price of gold spiraling upwards from a price that was pegged at $300/oz in March 2001 to more then $1,500 today. Gold isn’t the only source of mineral wealth in the country that may prove to be the largest copper deposits found anywhere on the planet. By 2004 the money started pouring in to Panama for exploration of mineral resources, and it is still pouring into the country.

The Isthmus of Panama was formed about three million years ago when huge amounts of sediments from both North and South America filled in the gaps between the islands of an island arc forming a solid strip of land that finally joined the two continents together. Many scientists feel this was one of the most important events that has occurred in the past 60 million years. Because it filled the gap between the Americas it completely changed the pattern of oceanic circulation that gave us the world’s present climates by forcing warm water northwards thereby heating the whole northern hemisphere. It also created a landbridge that allowed the plants and animals from the Americas to mingle.

Panama and the Panama Canal, The high mountains to the south of the canal are the home of much of the gold in the country, but gold is found throughout the country wherever there are volcanic mountains NASA

The islands were for the most part volcanic like the modern Lesser Antilles of the Caribbean Sea. These volcanoes are represented today by the string of volcanoes in Panama. It is these volcanoes inland from the subduction zone just off the west coast of Panama where the Cocos Plate is being subducted beneath Panama that keeps these remnants of volcanic islands still active today it also provides the heat engine that allowed the many mineral deposits to form.

Gold panning lessons. Public Domain

There are extensive deposits of placer gold in Panama with one of them in the southern part of the country more then 100 miles long along the banks of a river. Because of its tropical nature the placer deposits in the country have been little exploited although some artisanal native miners have been working these deposits for years.

Gold in Black Shale, Metal Extraction using Specially Cultivated Bacteria

2011-12-28T20:08:00.000-08:00

A settling pond in front of a heap leaching pile. USGS

Gold and other metals are found in black shale usually in quantities too small to mine economically using the old methods, but that is all changed with the introduction of a process called bioextraction that is closely related to bioremediation. The author has actually use this technique in his environmental consulting business to remediate industrial sites that were contaminated with heavy metals. This particular method of metal extraction makes use of local bacteria that are already present in the soils around the area of black shale.

A cultivated bacteria used to heap leach black shale. NOAA

This method of using the natural bacteria is completelygreen allowing the extraction of metals without soil contamination. Of using a solution of bacteria for extracting metals from black shale was developed in the mid-2,000s in Finland on another poly metallic black shale. The process is extremely inexpensive to operate and can be fine-tuned to extract different metals from the shale. The process itself is based upon heap leaching the shale after it has been ground up and piled in its better then sprinkled with the bacteria bearing solution. The pregnant bacteria solution is then pumped into a central point where the metal is extracted then the solution is recycled back into the heap leaching process.

Black shales are noted for their poly metallic mineraldeposits all over the world. One such black shale is the Marcellus shale found in the eastern United States that is now being exploited for its natural gas content. In the process of extracting the gas in the shale is Hydro Fracked so that after the gas is recovered a solution of the metal extraction bacteria could be pumped down the hole and allowed to extract any metals that are left in the shale.

Besides allowing the extraction of gold this process allows the recovery of virtually any other metal found associated with Black shales including rare earth elements. For just gold mining this process would obviate the use of cyanide or mercury for the extraction of gold. By fine tuning the process any number of other metals can be extracted. Since the source of the bacteria is from the same area as the mine is causing this to be a completely green process.

This is only of a number of other processes that can be adapted from existing metal remediation used in the environmental remediation practice. Once the proper bacteria are extracted from the environment and cultured there is no limit to the different types of metals that can be extracted using this process.

Gold Occurrences in Costa Rica

2011-12-24T16:05:00.000-08:00

Coat of Arms of Costa Rica

The very name Costa Rica in English means "Rich Coast" a country that has become the home to many expatriate Americans because of its stable government. What makes it favorable to so many gold hunters is the chain of volcanoes reaching from north to south through the country. There are several gold bearing regions found throughout the country associated with its volcanic nature.

The only producer in Costa Rico is presently “Inversiones Valle Columbia” that holds an exploitation concession right in the center of the historic Las Juntas mining district. There are two veins LaPita and the Olga that have been developed into mines feeding the mill that supplied ore running from 10 grams to 20 grams per ton that were supplying up to 80 tons of ore per day.

Volcan Arenal in Costa Rica
Photo by Matthius Prinke

The owner of Invesions Valle Columbia, Luis Canto bought the Rio Chiquito mine from Corporacion Minerales Laguna SA in 2002 that has stated resources of almost 177,000 tons. It’s his intention to prove and exploit this deposit that averages 11.18 g/t Au and 21.2 g/t Ag.

There is even a district in Costa Rico called the Montes de Oro, literally Mountains of Gold about 70 km west of the countries capital San Jose close to the town of Miramar overlooking the Pacific Ocean. This mine owned by Glencairn is producing up to 60,000 oz of gold per year. The property has produced gold off and on for more then a century.

At the Crucitas project Vannessa Ventures has acquired one of the premier gold producing areas in Costa Rico consisting of 10 concessions that cover 176 km² where they have already spent over US$34 million in exploration and development. Crucitas is ready for mine development containing measured, indicated and inferred resources of more then 2.4 million ounces of gold.

A long tradition of placer gold mining has affected the local population of the Osa Peninsula in Costa Rico. This goldfield that extends across three-quarters of the Peninsula has even managed to produce some large nuggets. In this area you can at least pan colors in your distinctive gold pan that was developed by the local populace for their mining conditions.

There are several concessions of placer gold for sale in Costa Rica including one of 10 km² in southwestern Costa Rica containing at least 7,500 kg of gold as stated by the Costa Rican Department of Geology.

This is similar to the subduction zone off the West Coast of Costa Rica.

A long subduction zone can be found off the west coast of Costa Rica that is the cause of so much volcanic activity in the country that supplies the “Heat Engine” necessary to build deposits of gold. This is not only applicable to Costa Rica, but anywhere on Earth where similar conditions are to be found. The whole west coast of the Americas have subduction zones laying just off their west coasts producing gold deposits from superheated water associated with the volcanism.

Gold Mines of the Future

2011-12-23T16:47:00.000-08:00

An underground waterfalls inside a gold mine. Crusier

Future gold mines and mines in general haven’t changed much except incrementally in more then a century, a situation that has to change as mines keep getting deeper and hotter. Theoretically it is possible to reach depths of 33,000 feet using existing technology, but at these depths human miners are not able to work efficiently calling for other technologies not depending on man. There have been many advances in the scienceof robotics that may fill some of these needs, but other technologies are going to be needed too. The engineering department of Laurentian University in Sudbury, Ontario is one of many organizations working on the problem of developing the Future Mine work is progressing at both the university level and in the R&D labs of mining companies.

One of the first things to vanish from mines in the future is the headframe that has been a hallmark of underground mines for centuries. The mine hoist will no longer be needed as in most mines the hoist and cables will be replaced with a Maglevsystem similar to that used today on Maglev railroads. There is no reason why the Maglev system won’t work vertically as well as horizontally.

Explosives that have been used in mines since the 17^th Century are another thing that is apt to be replaced by a system developed by Noranda Mines that makes use of high energy electricity that is stored in powerful condensers where the power is channeled into a drill hole filled with water that is ionized by having the electrical charge funneled into a thin copper wire between to steel rods. The resulting explosion caused by the ionized water is extremely powerful capable of pulverizing rock, and is far safer to use then conventional explosives.

The Tunnel Boring Machine (TBM) has already been successfully used for boring many tunnels throughout the world, one place where it has been used is in New York City where it has cut the tunnels for the New York Water Tunnel #3 that is 28 feet in diameter and many miles long. Variations of this system can be used to replace the system of drill and shoot that is presently used. The use of the TBM allows very small suzes some as small as a beer can used to follow small veins in the rock that are overlooked during today’s mining techniques.

One thing that is certain as man goes further into the Crust of the Earth in his quest for minerals man himself is apt to be left behind replaced by robots. Human miners will become redundant. One visionary even sees robots the size of ants being used in future mines that would spat a bacteria charged solution onto ore bearing rock that would dissolve the metals that then would be recovered from the resulting solution. Things they are achanging!

Strategic Alliances

2011-12-19T20:40:00.000-08:00

This is a group of companies providing goods and services to the mining and exploration industry. If you would like more information about our strategic allies they are listed below.

G&O Diamond Drilling Contractors is based out of Hay Lake, Alberta, Canada covers North America has over 40 years experience. Their crews are trained to provide not only core drilling, but many of the other skills needed in modern mining practices. You can contact them through the following link: http://coredrilling.ca/

The Sonic Goldblaster 100

Goldlands is a company in Bellingham, Washington that makes Big Boys Toys for large scale placer mining up to 150 tons per hour. You can contact them through the following link: www.goldlands.com

The World’s Deepest Gold Mine is cooled with Slush

2011-12-18T18:01:00.000-08:00

A South African goldmine similar to the one in this article.
Photo by Babakathy

There is a certain amount of argument as to what is the world's deepest gold mine, but there is no doubt it is found in the Witwatersrand of South Africa. The latest contender for the title of world's deepest mine is the Mponeng mine of the West Wits district of the Witwatersrand. The mine's name is derived from the Sotho word for “Look at me.” At 13,000 feet this presently holds the record as the worlds deepest mine. This record does not only apply to gold but any other product such as uranium that is mined from the deepest recesses of the earth.

This mine is so deep the only way it can be cooled to the highest temperature allowed by South African law of 83°F at the mine face is by refrigeration that makes a mixture of ice and water that we call slush. There is several refrigeration units deep in the bowels of the mine made by IDE Industries headquartered in Israel that make slush as part of a scheme to make fresh water from sea water . The slush is held in readiness in underground reservoirs until it is piped to the working face of the mine. After it has done its job of cooling the mine the warm water is pumped back to the surface where it originally came from by large electric pumps using tremendous amounts of electricity where it is allowed to cool off.

The mine contains 230 miles of shafts and tunnels that take the workers as much as 90 minutes to reach the working face of the mine allowing only five hours per shift at the working face. The shaft is split into two sections causing the workers to have to walk to the second shaft before they can continue their journey to the bottom of the mine. Most of the trip continues on rails that carry men, equipment and ore. The final part of the journey is made in low tunnels that cause the men to walk hunched over with their miners lamps to brush the ceiling of the tunnels. Some of the time they have to go down narrow stairways leading into the depths of the mine.

At present this mine is the deepest on earth, but it is possible to extend the depth of a mine to 33,000 feet with most of the work being done by robots. This mine makes it too all apparent that no real changes have taken place in deep mining for more then 100 years, a situation that must change if we are going to continue extracting minerals from the depths of the earth.

We welcome comments on this subject!

You don’t want to meet this guy while prospecting; a 15 foot diamondback rattlesnake

2011-12-17T15:13:00.000-08:00

The world's largest diamondback rattlesnake. Look at the sheriff's leg for a size comparison .

At fifteen feet this might be a new world’s record for the largest poisonous snake in the world. This nightmarish monster was recently caught in St. Johns County, Florida by the St. Johns Sheriffs Department. This snake was so big it looked more like a boa constrictor or python then a rattlesnake. This snake weighed around 170 pounds and is capable of swallowing a two year old child or one of your pets. The only poisonous snakes in the world that even approach this monster in size are the Bushmaster of Central and Northern South America or the King Cobra of Southern Asia. This snake is capable of striking for a distance of seven and a half feet with venom so powerful one bite is capable of killing 50 men. A bite from this snake is like having two quarter inch curved screwdrivers driven into your flesh. This huge diamondback was caught near the St. Augustine Outlet in a new subdivision of KB homes just south of Jacksonville, Florida.

The fangs of the largest rattlesnake. The blade on the knife is four inches long.

Rattlesnakes of this size are unusual, but it was in 2009 that one almost this big was caught in Alabama that was fourteen feet long, and weighed over 100 pounds. There are surly other monsters like this lurking around in the southeastern United States. The Eastern Diamondback is found as far north as North Carolina, and as far west as the Mississippi River. The snake is usually not as long averaging from 3.5 to 5.5 feet long although in one study an average length of 5.6 feet was found. According to the Guinness Book of Records as of 2009 the longest eastern diamondback on record was 7.6 feet. it is estimated this snake had been living since the late 1980s making you wonder if more of them are around, what they have been eating. how many others are there around like them and where are their offsprings or kin.

These snakes habitat is dry upland grassy areas although at times they can be found on dry hammocks in coastal wetlands. The author once encountered a whole hammock full of them in the Everglades. The eastern diamondback is an excellent swimmer so they may be encountered in swamps, lakes and rivers.

Another view of the largest rattlesnake showing a clear view of its head.

You may be wondering why this was included in Gold Mining & Prospecting this is because its habitat includes parts of the eastern goldbelt that extends through the southeast from Maryland to Alabama. This is the scene of the first Goldrush in the United States and because of recent exploration activity is becoming one of the hottest areas in North America for finding gold. You wouldn’t want to meet one of these guys on a prospecting trip because they could completely ruin your day. Even the little ones could, and there are at least three other poisonous snakes in the southeast United States, the Copperhead, the Coral Snake and the Cotton Mouth. Look out!

Followup: Further research on this story reveals it isn't true. Although the rattlesnake was a large specimen of its species what gave it its apparent size was because the photographer taking the pictures was closer to the snake then the sheriff was. Even if it wasn't 15 feet long a diamondback rattlesnake is still the largest and most poisonous snake in North America and should be respected.

In a further followup with Molly Davis a spokesperson with the St. John's County, Florida Sheriffs Department although the snake wasn't 15 feet long is was however a giant specimen nonetheless of an Eastern Diamondback. The snake hunter who wasn't allowed to keep live specimens killed the rattlesnake because of its proximity to a housing development. It was in some shrubbery at the entrance to the development where the snake was found.

This was an extremely dangerous animal with any member of the rattlesnake demanding much respect. It should be remembered that the newly born members of the rattlesnake clan are the most poisonous.

Building Stone Quarry for Sale in Massachusetts.

2011-12-04T01:40:00.000-08:00

Massachusetts in red.

For sale by owner a building stone quarry in the central Berkshires of Massachusetts. This quarry is a turnkey operation that is ready to go complete with permits. It produces flagstones and veneer from the famous Goshen stone a hard mica-schist that splits naturally into flat sheets of stone.

For further information contact John Carter at: geotekllc@gmail.com

Gold Occurrences in Nicaragua

2011-12-01T11:37:00.000-08:00

Coat of Arms of Nicaragua

Nicaragua is the largest country in the isthmus of Central America, and the second largest country in Central America after Hondas. Like the rest of Central America the country is amply endowed with gold and other minerals. The country is often referred to as the land of lakes and volcanoes. The presence of so many volcanoes is a sure sign that gold can be found throughout the country as both placer and lode deposits. A line of volcanoes runs from north to south; some of them are extinct and others are active. There are volcanoes having huge smoking mouths while others were blown away by violent eruptions leaving behind lakes that now occupy their calderas.

Gold mining is not an especially important component of Nicaragua’s economy although there are a few mines that have been producing gold since the 1940s. This producer id the Limon Mine belonging to Glencairn Gold Corporation. During a recent year this mine produced about 48,000 ounces of gold. Altogether this mine has produced approximately 2.7 million ounces of gold in the period from 1941 and ending in 1979. This was during the period when the mine was under the control of Noranda, a Canadian Mining Company. The property is still in production.

A recent discovery of epithermal gold has been made in the southeastern part of the country by Nuevo Guinea a project of Radius Gold. This is in an area of rolling farmland that is served by good roads from Managua making the extraction of gold an easy process. More work by Radius on its 100% owned San Pedro discovery that is about 200 km west of Managua in an area of epithermal quartz veins located anomalous high readings of gold in stream sediments that has returned values that range from a trace ti as high as 6.8 g/t of gold. There are several other occurrences of gold in Nicaragua that are undergoing exploration. Some of these projects are the El Pavon, Rio Luna, El Limon, La Libertad and La India.

Nicaragua like most of the rest of Central America has been built up from a subduction zone that lies just off the west coast of the area. It most probably began as an island arc with the islands through volcanic action becoming one continuous strip of land. It was this volcanic action that caused the gold to be deposited in epithermal deposits. Many times the hot gold bearing water found a place to be deposited in fault and shear zones. Many of these deposits are apt to be traced over kilometers in length and width.

At one point in the development of the area the subduction zone split giving rise to the Caribbean Islands that in the more recent Lesser Antilles are mainly volcanic, the Greater Antilles are all known to be gold bearing, but it must be remembered these islands share a common ancestry with Central America.

Gold Occurrences in Guatemala

2011-11-28T18:05:00.000-08:00

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 20^th 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.

Gold Occurrences in Honduras

2011-11-26T15:01:00.000-08:00

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!

Gold Occurrences in Greenland

2011-11-22T11:13:00.000-08:00

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 York. Northern 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 Toronto. Greenland 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 19^th 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.

Gold Occurrences in Mexico

2011-11-20T10:21:00.000-08:00

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.

Gold Occurrences in Nunavut

2011-11-17T11:32:00.000-08:00

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.

Gold Occurrences in the Northwest Territory of Canada

2011-11-15T11:52:00.000-08:00

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.