What is the true value of gold?

What is the true value of gold?

There’s something about gold. It possesses us, sometimes entire nations to accumulate more and more of it. Humans have had a strong affinity for gold since the times of the ancient Egyptians and the Aztecs. Gold has been used as currency for thousands of years. Wars have been fought for it, entire civilizations slaughtered for their gold.  Pindar, the ancient Greek poet, described gold as “a child of Zeus, neither moth or rust devoureth it, but the mind of man is devoured by this supreme possession.”

goldCoins

It’s hard to describe the feeling of finding your first gold nugget in an old stream bed.  It sits there in your pan shimmering, the way that only gold can.  You immediately recognize it’s power, it is intoxicating.  This is what drives prospectors past and present to take great risks in the search for gold.  There’s more than just the value of gold that attracts us to it.  The word “placer” itself comes from the Spanish word meaning “pleasure”. For some it is an addiction, for others it symbolizes wealth. You’ll be hard pressed to find a member of the human species who wouldn’t be interested in some gold.

Gold has several properties that make it desirable.  Most importantly it does not rust or tarnish.  Gold artwork discovered in the tombs of Egypt looks just as lustrous today as it did 5000 years ago.  Why is that?  Gold belongs to a group of metals called the “Noble Metals”.  They’re called noble because like nobility in old time monarchies they don’t associate with others.  It’s fancy way of saying that the metals don’t readily react.  Conversely iron will readily react with oxygen to form iron oxide (aka rust).  Gold and other noble metals, such as platinum, possess a very strong atomic structure that requires a lot of energy to disrupt.

KingTut

The ability to maintain over time is common of all valuable substances.  A diamond for example produces a characteristic glow when cut and faceted properly but what good would it be if it disintegrated a month later?  Diamonds are extremely hard and have a rock solid crystal structure.  Other valuable gemstones all share similar properties, emeralds, rubies, sapphires and garnets all sit at the high end of the hardness scale.  While gold isn’t hard in a geological sense it maintains it’s shape and luster indefinitely.

Gold is also very malleable.  Meaning that it can be hammered or pressed into various shapes without cracking or losing its consistency.  You could stretch an ounce of gold into a wire 80km long or produce a sheet of gold leaf 80 meters by 80 meters wide.  Gold is also an excellent conductor.  Not quite as good as copper but a better conductor than nickel, brass, iron, tin, and aluminium.  Gold conductive wire is used in many critical electronics applications such as computer motherboards, smart phones and satellites.

CarajasMine
Carajás iron mine, Brazil

What really makes gold valuable though is it’s scarcity at the earth’s surface.  Approximately 165,000 metric tons of gold have been produced in the entirety of human history.  While that may sound like a lot the amount of gold produced by mining is extremely small in comparison to other metals.  For example the Carajás Mine in Brazil produces an average of 300 million metric tons of iron per year and has a deposit estimated at 7.2 billion metric tons.  And that’s just one mine.  All the gold ever produced would fit inside one Olympic sized swimming pool.

It is often stated that you can’t eat gold.  While that’s not entirely true, (see gold covered pizza) an all gold diet wouldn’t provide much nutrition, and you’d probably have some digestive issues.  The yellow metal doesn’t appeal to our basic needs for survival but neither does money or a smartphone.  That doesn’t make any of these things less valuable.

gold-400oz-bar

 

We typically think of value in dollar terms.  When evaluating an investment such as stocks or real estate it’s hard to think of anything else.  Dollars are not constant though, they are subject to manipulation and inflation.  For at least 6000 years gold has been used as currency and unlike modern currency is not subject to inflation.  Modern currencies are what is called “Fiat Currency”.  There is no standard on what a modern currency note can be exchanged for.  Their value relies solely on people’s faith in it.  Or more correctly their faith in the government.  Inflation rates can severely affect the spending power of a dollar.  There are countless examples, the most striking is the inflation of the German Reichsmark which rose from 4.2 marks to USD in 1914 to a peak of around 4.2 trillion marks to the US dollar by November 1923.  At that time a wheelbarrow full of German marks wouldn’t even buy a newspaper.

Historically world currencies were backed by the gold standard which meant that by law any amount of paper money could be exchanged for a specified amount of gold.  In the 1920s each US dollar was backed by 1.5 grams of gold.  The dropping of the gold standard in Germany during WWI allowed for the hyperinflation that followed.  The United States dropped the standard during the great depression to avoid the federal gold supply from being completely depleted.  Canada followed suit in 1933.  There’s much debate on the merits of dropping the gold standard.  What resulted though is the ability for the government to completely control the currency without requiring tangible assets (ie. gold) to back it up.

Gold bars
Gold bars

So if the dollar is backed by nothing and can be manipulated at will how do you gauge the value of gold.  Or anything for that matter.  True value depends on what people are willing to trade for your goods.  Money makes it easy to barter and trade goods since it’s ubiquitous and there is an agreed upon value at any given time.  For example if you want to sell your car on craigslist you’ll have an idea of how many dollars you want for it.  Lets say you have a used Honda Civic.  You could sell that easily for $4000 CAD.  That same Honda Civic could be traded for a 1 carat diamond engagement ring.  50 years from now a used car might sell for $25,000 dollars due to inflation but the exchange rate of car to diamond ring would remain the same.

The old adage that an ounce of gold will buy you a nice suit still rings true today.  In the gold rush era (1848-1900) an ounce of gold would trade for about $20 USD, and would also buy a nice suit.  A typical suit today would cost you about $450 USD.  So it would seem that today’s gold would buy you 3.5 nice suits.  You have to consider that in the 1800s nice clothing was not mass produced.  To compare accurately you’d have to look at a tailored suit.  A mid range tailored suit made in the United States costs between $1650 and $1800 today.   At present gold is trading at about $1250 USD so the suit adage falls just above the quoted dollar value of gold.

Indian River Yukon

What really gives gold it’s value is the cost of exploration and production.  Being very rare it takes a lot of effort to find gold.  Once it’s found it is expensive to produce as well.   For example Barrick’s Cortez mine in Nevada has an average grade of 2.11 grams per ton.  That means that for every ton of ore processed they average 2.11 grams of gold.  Barrick’s published production cost at the Cortez mine is about $900/oz.  It really is remarkable that they can move and process the 15 tons of rock required to obtain an ounce of gold for $900.

The cost of producing an ounce of gold varies for each mine.  In a placer operation it is a constant cat and mouse game to keep costs low enough to make production economical.  When gold commodity prices fall below production costs mines shut down and less and less gold is produced.  The production cost, driven by scarcity is the single most important factor that drives the price of gold.

RC Drill in Action

Gold exploration is also very expensive.  In the times of the North American gold rush placer and hard rock gold was discovered all over the Western part of the continent.  From the 1840s to 1900 new gold districts were popping up every year as discoveries were made.  Trending almost in sequence Northward from California to the Yukon as explorers made their way through the wilderness.  In more modern times most of the easily reachable areas have have been at least partially explored.  Exploration today mostly takes place in more and more remote areas, such as the Canadian Arctic or other places with a small human footprint.

To properly explore a claim in these areas requires a camp. helicopters and all kinds of equipment.  A typical small exploration program in the Northwest Territories can cost well over $1,000,000 per season with slim chances of success.  While advancements in exploration technology such as geophysics and aerial imagery can provide information that wasn’t available to previous explorers there is no silver bullet.

The costs of thousands of exploration ventures that didn’t amount to a mine are factored into the price of gold as well.  For the estimated 100,000 explorers that took part in the Yukon gold rush only a select few managed to recoup their costs.  Some made made great discoveries but many more spent their life savings on an adventure but returned with no gold.

Big Al Jig

Gold’s value is based on it’s unique properties, people’s desire for the very special metal and the work required to find and produce it.  The value has nothing to do with the the dollar value attached to it.  For every ounce of gold produced tons of rock had to be excavated, the deposit had to be discovered and mapped, and the ore milled and smelted to extract the gold.  As you gaze upon your gold ring and admire it’s beauty think about the story that it could tell you.

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Mining the Ocean Floor with Robots

Mining the Ocean Floor with Robots

Mining under Earth’s oceans is just starting to happen.  We have gotten pretty good at mining deposits that are accessible by land but 71% of the Earth’s surface is covered by water.  To date no large scale mining operation has succeed under the ocean which means that it’s all virgin ground.

Amazingly the human race has spent more time and money exploring outer space than we have under our own oceans.  Over 500 people have been to space while only three have ventured to the deepest part of the ocean, the Mariana Trench.  We have better maps of the surface of Mars than the bottom of the ocean, although the ocean maps are pretty cool.

ocean_floor_map

The same geological processes that happen on land also take place under the ocean.  There are volcanoes, mountain chains, faults and earthquakes.  All the same types of mineral deposits occur under the ocean such as epithermal gold, porphyry, and placer.  There are also diamond pipes, massive sulphides and everything else that we mine at the surface.

Deposits

The ocean also has types of deposits that we can’t find on land.  One special mineral deposit is called Polymetallic Nodules.  These are concretions of metallic minerals that occur under the ocean.  The nodules grow sort of like stalactites do in a cave, over time layers of metallic minerals precipitate out of seawater and add to the nodule.  The growth of nodules is one of the slowest known geological processes taking place at a rate of one centimetre over several million years.

noduleBig2nodules_floor

Polymetallic nodules are roughly the size and shape of a potato and contain primarily manganese as well as nickel, copper, cobalt and iron.  They can be found on the sea floor or buried in the sediment.  Nodules can technically occur anywhere in the ocean but seem to be in greatest abundance on the abyssal planes around 5000m deep.  Nodule mining would be similar to placer gold mining except under water.

Anouther resource that is unique to the ocean floor is Ferromanganese Crusts.  These are similar to nodules but occur as a coating on other rocks.  These crusts can be found all over the ocean with thicknesses ranging from 1mm to 26cm.  Ferromanganese crusts typically occur in the vicinity of underwater volcanoes called seamounts or near hydrothermal vents.  Crusts with mineral grades that are of economic interest are commonly found at depths between 800m and 2500m.

Crust
Ferromanganese Crust

Ferromanganese crusts are composed primarily of iron and manganese, hence the name.  Typical concentrations are about 18% iron and 21% manganese.  Cobalt, Nickel and Copper occur in significant quantities as well.  Rare earth metals such as Tellurium and Yttrium can be found in metallic crusts at much higher concentrations than can be found on the surface.  Tellurium is used in solar panels and is quite valuable.

Sea-floor massive sulphides (SMS) are a younger version of volcanic massive sulphides (VMS).  The two deposits are similar except that VMS are typically ancient and SMS are currently forming.  SMS deposits occur where superheated hydrothermal fluids are expelled into the ocean.  They typically form around black smokers near continental rift zones.  SMS are know to hold economic concentrations of Gold, Copper, Silver, Lead, Nickel and Zinc.

BlackSmokerHiRes
BlackSmoker

Black smokers create SMS deposits by expelling superheated sea water that is rich in metallic elements.  Cold sea water is forced through the sea floor by the pressure created from the weight of the water column above it.  The water is then heated to temperatures in excess of 600°C when it is brought close to the magma that lies below.  The heated water becomes acitic and carries with it a high concentration of metals pulled from the surrounding rocks.  Once the hot, metal rich, water comes into contact with cold sea water the metals crystallize and deposit on and around the black smoker.

Mining

Large scale ocean floor mining has not taken off yet.  Attempts have been made since the 1960s and 70s  but failed due to technological and financial challenges.  Small scale shallow ocean mining has been a lot more succesful in recent years.  A great example is the popular TV show Bering Sea Gold.  The miners in Nome Alaska are using modified suction dredges to comb the sea floor in shallow waters.

Currently proposed sea floor mining ideas are essentially super high-tech placer mining.  They involve ways to dig through the surface layers of the ocean floor, bring the material to the surface and ship it to a processing facility.  Its a lot like dredging but on a massive scale.  As mentioned above, normal hard rock deposits also occur under the ocean but no plans have been proposed to build open pit mines under the ocean.  That would involve all the challenges of building a mine on land with the added complexity of operating under the ocean.

Why is ocean floor mining possible now when it wasn’t 20 years ago?  The answer comes down to one word, robots.  The world of under water mining is the domain of autonomous drones and human controlled ROVs.  Robot submarines are nothing new, they have been around since the 70s and have been used to explore depths of the ocean that are very difficult for humans to get to.  UUVs or unmanned underwater vehicles are a little bit newer, they are basically an autonomous version of ROVs.  Ocean mining robots have just been invented and share a lot of the technology used in these devices and they look like something straight out of science fiction.

cutter
The Cutter

The first deep sea mining project is currently being developed off the coast of Papua New Guinea.  The project is called Solwara 1 and is being developed by a Vancouver BC mining company called Nautilus Minerals.  Solwara 1 is a copper/gold SMS deposit with estimated copper grades of 7% and gold grades in excess of 20g/t and an average gold grade of 6g/t.  The property sits at about 1600m depth.

Nautilus has developed a suite of underwater mining robots and a complete system to mine the precious metal and bring it to shore.  There will be the bulk cutter pictured above, an auxiliary and a collection machine.  Please take a moment and marvel at these amazing achievements of engineering.

Transporter Bridge TeessideTransporter Bridge Teesside
 After the robots dig up and collect the ore a custom designed Riser and Lift System (RLS) will bring the material to a giant ship that acts as the mine control center dubbed the Production Support Vessel (PSV).  The RLS is basically the world’s most powerful suction dredge.  It’s pretty complex, this is the description on the Nautilus Minerals website:

The Riser and Lifting System (RALS) is designed to lift the mineralised material to the Production Support Vessel (PSV) using a Subsea Slurry Lift Pump (SSLP) and a vertical riser system. The seawater/rock is delivered into the SSLP at the base of the riser, where it is pumped to the surface via a gravity tensioned riser suspended from the PSV.

Once aboard the Production Support Vessel the mined slurry will be dewatered and stored until anouther ship comes to take the material on shore for processing.  The removed sea water is pumped back down the RALS which adds hydraulic power to the system.  Pretty cool stuff!  Check out the video below for an visual explanation of how it will all work.

Exploration

Ocean floor prospecting is not a good place to be gold panning or hiking around with a rock hammer.  It is also difficult to take usable photos due to poor light and lots of debris in the water.  So how do you explore for minerals in the ocean?  Geophysics and robots.

Geophysical exploration is not unique to the ocean.  The same techniques are used routinely on land to find every type of mineral deposit.  Ocean geophysics is also not new.  The main workhorse of mining exploration is magnetometry.  Which means mapping changes in earth’s magnetic field using a specialized sensor.  The technique was actually developed to detect enemy submarines during World War II.  Since then magnetometers and the science behind them have evolved into accurate tools to measure geology.

I’m using a proton precession magnetometer in the photo below.  There is some sample magnetometer data on the left.  Mag maps look similar to a thermal image except the colour scale represents magnetic field changes (measured in nanoTesla) instead of temperature.

Walk Mag in ActionSampleMag

Magnetometers are excellent tools for ocean mining exploration.  They are not affected by the water and are excellent at detecting metallic anomalies.  There are now underwater drones that can collect ocean magnetometer surveys without the need for human intervention.

Autonomous Magnetometer Drone
Autonomous Magnetometer Drone

Other geophysical techniques have been used in ocean mineral exploration.  Electomagnetics (EM) techniques are also great tools for exploration under water.  EM works in a similar way to magnetometry except that they emit their own source.  Conventional metal detectors are actually a small version of an EM system.  While mag passively measures Earth’s magnetic field EM measures the difference between a source and received pulse.  EM also works great for discovering metallic anomalies and is being incorporated into autonomous drones as well.

There are other types of ocean geophysics such as seismic refraction which uses a giant air gun to send a sound wave deep into the crust and measures the response on floating hydrophones.  Sonar and other forms of bathymetry can provide detailed maps of the ocean floor.  Bathymetry techniques can create imagery similar to LiDAR that is used on land.

Sample Bathymetry
Sample Bathymetry

Ocean mining is just in its infancy and some really cool technology is being used.  Advancements in the robotics have allowed mining and exploration to be completed without a person having into enter the water.  As technology advances further we will be able to explore vast areas of the ocean floor and discover immense mineral reserves that are presently unknown.  It is estimated that we have only explored about 5% of the ocean floor, who knows what we’ll find down there?

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How Much Gold is Left on Earth?

How Much Gold is Left on Earth?

Is the world running out of gold?  That seems to be a common theme in investment circles in recent years.  This eye catching article on Visual Capitalist estimates that we’ll be out of gold by 2030. This article based on a report from Goldman Sachs claims we’d hit “peak gold” in 2015, GoldCore.
Gold_reservePeak gold is the same idea as peak oil.  Where the peak is the moment when maximum world production is reached and declines from then on, eventually reaching zero production.  Unlike oil though gold is not used up in consumption.  It is typically stashed away in a vault or worn as jewellery.

Estimates for all the gold in the world mined to date hover around 165,000 metric tons.  Some estimates go as high as 1 million tons but most experts would agree that under 200,000 is accurate.  World gold supplies are difficult to quantify. That is because gold reserves are not always reported accurately.  Over 50% of gold above ground is used for jewellery which makes it difficult to track.  Gold rings, necklaces and such can change hands without any records.  About 35% is stored as bullion for investments and reserves.  Large holders of gold give misleading numbers regarding their reserves, presumably for security reasons but who knows?

pourLiquidGold

The United States, Germany, Italy and France are the worlds largest holders of gold respectively.  Each has their share of controversy surrounding their claimed gold deposits.  There are conspiracy theories about the amount of gold stored in Fort Knox.  Some believe it is empty and the government is just pretending its full of gold.  Without seeing it for ourselves we’ll just have to accept the disclosed numbers.

To further add uncertainty to global gold production small scale miners do not typically report their take.  This is especially true in third world countries.  A lot of gold is mined in this way, primarily placer but hard rock as well.

AfricaMiners

How much gold is left in the ground?  Nobody really knows.  Mining companies of all sizes spend their exploration budget to map out potential deposits.  They are a long ways from mapping the entire earth.  The peak gold estimates are based on proven and indicated reserves that are reported by public mining companies.

There is no shortage of gold on earth.  The problem is that it is much deeper than we can mine.   Current scientific theories estimate that there is enough gold in the core to cover the surface of the earth with a 4 meter thick layer of pure gold.  The density of the core is measured using several techniques including seismic geophysics.  Seismic waves are measured from earthquakes all over the world.  The wave properties change as they pass through the liquid outer core and the super dense inner core.  S-waves can’t travel through liquid, that is how the outer core is mapped.  The density of the inner core is greater than iron at 5,515 kg/m3.  Clearly there are large amounts of substances that are heavier than iron to achieve that density.

seismicCoreMeasure

We are limited to several thousand meters below the surface as far as mining is concerned.  Check out this blog post on the origins of gold.

Lets do a little math.  The average concentration of gold in Earth’s crust is estimated to be between 0.0011 ppm(source) and 0.0031 ppm(source).  Now we can calculate the volume of the portion of the crust which can potentially be mined.  The deepest gold mine in the World is TauTona Mine in South Africa which reaches 3.9 kilometers below ground.  The TauTona mine, operated by AngloGold Ashanti, is a gold mine so its a good yard stick for how deep we can go.

The volume of the earth (approximated as a sphere) is 1,086,832,411,937 cubic kilometres.  The calculated volume for the earth with 4km stripped off the top is 1,084,788,886,213 km3.  Subtracting the two and using the average abundance of 0.0031 ppm we arrive at 6.3 billion cubic meters of gold in the top 4km of the crust.  One more calculation, gold has a known density of 19.3 tons per m3.  Which gives us a total mass of 122,264,143,828 or 122 billion metric tons.  That is a lot of gold.

Nuggets

Our calculated estimate of 122 billion metric tons of theoretical gold includes the entire surface of the earth.  Currently we are not equipped to mine the oceans, although technology is advancing quickly.  Check out this article on sub-sea mining robots, LINK.  The same processes that accumulate gold into deposits occur in the ocean just as they do on land.  With 71% of the surface covered by ocean that is a significant area that is yet to be explored.
earth-core
Lets adjust our estimate to account for only continental land which can be mined with today’s technology.  So by subtracting the oceans we are left with 35 billion tons of gold on dry land.

Global production throughout the entirety of human history is 165,000 metric tons as previously mentioned.  So in a very theoretical sense we have mined 0.00047% of the world’s surface gold.  That’s very encouraging.  Although not all of that gold is accumulated in mineable deposits.  Typically you need at least 0.5 ppm to make a mine profitable.  Depending on logistics, location, overburden and other factors that cut off grade can rise quite steeply.  So all of that 35 billion tons is not really available to us.

IMG_1741

Once gold is discovered it will be mined.  We are too greedy to leave it in the ground.  Take a look at the gold rushes of North America between 1849-1900.  There are some great blog posts on the subject here, Gold Rushes.  The hoard of gold hungry prospectors would descend on a creek once a discovery was made.  They would move in, erect a town and mine it for all its worth.  Within 2-3 years all the easy gold is gone and only the tenacious miners would remain to mine the small gold.  The rush would continue elsewhere and repeat the cycle.  The same thing happens with hard rock mining but on a longer time scale.

Peak gold takes this phenomena into account.  Much like peak oil we’ve picked the low hanging fruit wherever it has been found.  Gold is a little different because it is very hard to find.  When it comes to oil reserves the big ones stick out like a sore thumb.

MineBarrick

Typically it takes about 20 years to go from discovery to full scale gold mine.  That involves all the steps to test a property using prospecting, geophysics, and diamond drilling.  Delineating the reserve and all the stuff that it takes to build a modern mine (permits, studies, infrastructure and so on).

With the current state of the mineral exploration that 20 year lead time is going to come back to bite us.  Over the last few years mineral exploration has dropped off to the point that it is almost non-existent.  That seems counter-intuitive if we are running out of gold.  Exploration is a high risk investment and people don’t take the risk unless commodity prices are high.  The good news is that when prices spike again like they did in 2010 there will be a massive feeding frenzy.

IMG_1746

So we’ve estimated that within 4000m of the surface of Earth’s crust there is 35 billion tons of gold.  With a remaining 87 billion under the ocean.  Only a small portion of that is concentrated enough to mine.  Its a big world out there and we’ve only properly explored small pockets of it.  The super easy stuff is largely gone but with advancements in technology and some ingenuity its there for the taking.  For those explorers who are willing to put on their thinking cap and step outside of their comfort zone there is a bonanza waiting for us.

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UAV Applications in Mining

UAV Applications in Mining

Unmanned Aerial Vehicles (UAVs) are in the process of changing many industries.  Before UAV technology matured into a safe, reliable and low cost system aerial data was acquired by full size human piloted aircraft and was very expensive.  With today’s drones aerial data is cheaper, quicker and more creative than ever before.

droneMining

The mining industry stands to benefit greatly from new advances in aerial data acquisition.  In many cases drones are already being used in mining and in the coming years will be almost ubiquitous.

Drones offer huge advantages in every part of the mining life cycle including Exploration, Planning/Permitting, Mining Operations and Reclamation.

Exploration

DroneBanner

Mineral properties are often in remote areas where existing maps are either non-existent or of poor resolution.  In early stage exploration it is beneficial to have a quick overview of the prospect area.  In the past this would have been acquired by a conventional aerial photography company.  This would come with a large price tag.  As a result aerial mapping surveys would not be conducted until later stages of exploration.

Today a drone can do a better job for less money.  Drones can map an area in high resolution in less than a day, usually a couple of hours.  The cameras on today’s drones have benefited from advancements in small high resolution sensors. Miniaturization of other components such as GPS and computer boards has also contributed to the modern drone.  Due to the unmanned nature of a drone it can fly close to the ground which allows unparalleled image resolution.  Conventional aerial survey aircraft require camera’s with extremely high resolution (80mp and up) because they fly at elevations of 2000-5000 ft above the survey area.  Drones can fly at 250 ft with a 16mp camera and get better data.

Satellite imagery has come a long way as well but does not come close to the quality of drone data and the cost is still prohibitive.  The best satellite data today is provided by the WorldView-3 satellite at 31cm/px.  Drones can produce 4.0cm/px or better.  You can forget about Google Earth, their resolution is no better than 65cm/px.

Early stage exploration projects can now get a rapid aerial image mosaic produced by a drone for a couple thousand dollars.  Where a conventional aircraft would produce an inferior product for about ten times the cost.  This cost advantage allows imagery to be collected very early in the exploration process when it can be of the most benefit.

In addition to aerial imagery the same drone data can be used to produce accurate topographical maps and GIS data in remote areas.  Topo mapping was previously produced by ground surveyors with an RTK/GPS rover.  You would have to pay a survey crew to walk the entire property and collect GPS points to be used in a map.  Mapping drones can do this today without the need for any ground control points at all!

Strati.jpg.pagespeed.ce.51mTrkbnOw

The combination of low cost aerial imagery and terrain data allow modern explorers to have a close up view of any property in 3D.  Having this capability in early stage exploration aids significantly in project planning.  Drones can provide support for mineral exploration in the following areas:

  • Terrain Assessment
  • Geomorphology
  • Outcrop Detection
  • Wildlife and Environmental Assessment
  • Drill, Showing and Equipment Location
  • Up to date imagery of the property

Remote sensing has huge applications in prospecting as well.  In the years to come sensors such as infrared, hyper/multispectral cameras and LiDAR will improve upon existing satellite based techniques to map underground river systems and directly identify mineral bearing outcrops.

Aerial geophysics is making its way into drones too.  I was involved in the development of a large scale drone from 2011-2013 designed to conduct long range aerial magnetometer surveys.  It was a great advancement but sadly the company suffered from poor management.  A few other companies have developed magnetometer drones in recent years too.  Drone geophysics has the same advantages over conventional aircraft such as low acquisition cost and rapid deployment.

Venturer Geophysics Drone
Prototype Long Range Geophysics Drone in 2012

Planning/Permitting

In the development stage drones offer unparalleled advantages to mining companies.  One of the biggest hurdles in developing a mine is environmental permitting.  Low cost drone imagery can map a mining property in incredible detail.  Aerial photos allow mine planners to easily locate and map:

  • Trees/vegetation
  • Streams, Rivers and Lakes
  • Wildlife Counts
  • Existing Roads, infrastructure
  • Before/After Ground Disturbance

Having aerial photos of an area before mining takes place will give an honest account of what the land was like when it comes to reclamation.  Wildlife counts and mapping of the ecosystem are crucial in development of environmental impact assessments.

Prototype LiDAR on drone
Prototype LiDAR on drone
Wing-tip magnetometer on a drone
Wing-tip magnetometer on a drone

 

 

 

 

 

 

 

Three dimensional mapping has been used in mine development for decades.  This data is relied on by mine planners to develop the mine itself, roads, tailings ponds, electrical infrastructure, and pretty much everything.  The main tool used is LiDAR which is a laser scanner that produces a high resolution 3D model.  Drones can produce the same data for less money.  LiDAR sensors are just starting to be installed on drones.  Photogrammetry can produce the same quality of model as LiDAR as well but cannot separate trees from ground as effectively.

Photogrammetry and LiDAR data are used for:

  • Mine pit development
  • Tailings pond design
  • Cost effective power line routes
  • Development of access roads
  • Geological Assessment

Mining Operations

Ore Pile Volumetrics
Ore Pile Volumetrics

In the operation/mining phase drones have a lot to offer.  One of the most widely used applications of drones in mining today in in stockpile volumetrics.  That is the 3D volume calculation of pile of waste rock or ore piles.  Having volumetric surveys completed at regular intervals will give an accurate measurement of how much material has been moved in that time.  This is important for many reasons.  Historically stock pile measurements have been conducted by ground surveyors with GPS rovers.  Many mines are still operating this way today.  Drone can do the same job without the need to pay for survey crews or to put people in a potentially dangerous situation.

Drones can provide detailed modelling and imagery of pit walls and slope stability.  Fixed-wing and multirotor inspection drones can get a close up, detailed image of potential points of failure in a pit wall.  Smaller multirotor drones are starting to be used to map underground mines too, offering the same advantages.

3D pit models can be done for a surprisingly low cost.  West Coast Placer conducted a pit mapping survey for a coal mine this summer and the results were amazing.  Check out the above video for a sample.  Mine engineers were able to use our data in their mine planning software (Minesight) to aid in development of the mine.  Like stockpile volumetrics pit mapping will provide a useful record of mine activity when repeated at a regular interval.  The low cost of drone data makes repeated surveys feasible on any budget.

Environmental monitoring is a part of active mines too.  As discussed drone aerial data offers huge advantages to environmental monitoring teams.  In the event of an accident or disaster drones can provide a detailed image of the event as it happens.  When the Mount Polley mine near Likely, BC had their tailing dam disaster in 2014 drones were used to map the extent of the damage.  The same drone company provided updates as the clean up progressed.

Reclamation

reclamation

During reclamation it is required to show before and after imagery to prove that a mining company is upholding their obligations.  Accurate three dimensional data acquired by UAVs helps mines return the terrain of a mine as close as possible to its original state.  Periodic surveys can show the progress as an ecosystem returns to it’s pre-mining conditions.

Currently in 2015 drones are just beginning to be used in mining.  There are a few intrepid drone service providers like West Coast Placer offering amazing products for prices that are 1/4 or less of what traditional aircraft would cost.  In the coming years we are going to see more and more drones operating on mine sites.  It will be standard equipment for explorers, miners and environmental teams in the not too distant future.

Check out our drones page to see the drone services provided by WestCoastPlacer.

 

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How Do Drones Work?

How Do Drones Work?

Five years ago you rarely heard the word “drone”.  When you did it brought up images of military air strikes and futuristic sci-fi movies.  In 2015 drones have become commonplace and are starting to be used in many industries.  A drone provides many advantages over traditional fixed wing data collection and the low cost makes it a practical solution to many problems.  Hobbyists are also quickly getting into the game due to dropping prices.  It is amazing how many people will drop $1000 or more on these high tech gadgets.

Drone FPV

Drones, also called Unmanned Aerial Vehicles (UAVs),  are flying robots that are able to execute a task autonomously.  They come in several different forms but they all have the same core components.  The four critical drone components are Autopilot, Propulsion, Sensors, Payload.

The Autopilot

The autopilot is the essence of what makes a drone.  In order for an aircraft to be called a drone it must have the capability to fly without human intervention.  The usage of the word drone has been misconstrued in recent years.  Just because an R/C aircraft has four rotors and a camera does not make it a drone, it muse have autonomous flight capabilities.  Autopilots are sort of the brain of a drone.  They monitor all the information coming in from the sensors and send signals to the control mechanisms based on their programming.

GlobalHawk

The autopilot software functions much like a thermostat.  For example if the drone’s alitutde is set at a certain number the autopilot will contol the aircraft to maintain that number.  If the drone rises higher the autopilot will adjust the controls so that the drone descends, if its too low it will set the controls to climb.  The autopilot operates in this way for hundreds of different parameters such as airspeed, altitude, GPS position, attitude (3D orientation), and many more.

The use of autopilots goes back to at least the late 1940s when experimental aircraft were able to operate completely by computer control.  Modern commercial airliners actually employ autopilots that can control the aircraft from takeoff to landing, the only thing they can’t do is taxi.  Every time you fly on a commercial jet you are riding a large autonomous robot.

For a flight to be successful the autopilot must have the parameters for the flight such as flight path, altitude, flight restrictions and settings stored in its memory before takeoff.  Once in flight the autopilot will use the preprogrammed information to follow a flight pattern and land at a predetermined location.  Watching an autonomous drone in action is quite an experience, they can give the impression that they are thinking for themselves.

PitotInvestigation001
Pitot Tube

The Sensors

Sensors on a drone connect it to the real world.  They perform the functions that the eyes, ears, nose and other senses do in a human.  A drone can only know what the sensors tell the autopilot, much a like a human’s concept of the world is based on what we can see, smell, hear and touch.  For example a drone will not have any idea it is heading directly for a tree unless it is equipped with an obstacle avoidance system.  The same is true of hitting the ground or a person who walked in front of the aircraft.  The pitot/static system is used to measure the current airspeed and altitude.  This sensor measures air pressure from a forward facing tube, as air speed increases so does the pressure.  The static tube measures the change in barometric pressure which decreases with altitude.  The pitot system also measures the wind speed by comparing the airspeed to the GPS speed.

drones-Communication

Most drones have a GPS system which is the basis for autonomous flight plans, and in the case of very accurate GPS systems altitude can be measured.  Drones also have a 3 axis accelerometer which monitors the aircraft’s orientation relative to the horizon.  Accelerometers are also used in smart phones, they are the device that senses when you shake or tilt the phone.  More complex drones have fancy inertial measurement units (IMUs) which use gyroscopes and other methods.  Drones have servos which monitor and adjust the position of control surfaces such as ailerons, or rudders.  Servos are electric motors that are calibrated to precisely place their control arm.  There are countless optional sensors which can add new capabilities to a drone.  Some optional sensors are altitude lasers or radar, trasnponders, voltage sensors, magnetic compass, and obstacle avoidance sensors.

killerDrone

The Propulsion System

There are a variety of propulsion techniques in use in drones today.  The majority of drones use electric motors.  The typical drone that most people would think of is a multirotor helicopter.  These use electric motors with a propeller on each.  Thrust of each motor is carefully controlled to maintain the correct speed, altitude and attitude of the drone.  Small fixed wing drones often use electric motors too although usually just one.  They are typically propeller driven as well and they work together with the control surfaces to make a flight successful.  Electric motors rely on battery power and can fly as long as the batteries hold a charge

Gas or heavy fuel motors are used on larger fixed wing drones and are still usually propeller driven.  There are a few drones out there using jet and turboprop engines such as the Reaper (armed version of Predator).  Rocket engines have been used for decades in target drones.  Targets were one of the first uses of drones by the military.  Its hard to believe but military forces around the world routinely shoot target drones which cost $20,000 and up each.  Gas or rocket drones run on a fuel source and their flight duration depends on how long the fuel lasts.  Gas drones also have batteries for their electric components and some of them have an on board generator.

I was part of the team that developed this drone
I was part of the team that developed this drone

The Payload

Quad
Payload is often the area where the most development work is focused.  After all these robots are flying for a purpose.  The most common payload is some form of a camera.  The majority of drones out there are either taking photos or video.  Most small drones consist of a multirotor with a GoPro camera on a gimbal.  Mapping drones like the one used by WestCoastPlacer have a down facing high resolution camera that is triggered by the autopilot.  Mapping drones also record the GPS position and aircraft orientation with each photo for use in processing.  Different kinds of cameras can be used such as infrared, multispectral and hyperspectral.
Camera mounts that I designed in 2012
Camera mounts that I designed in 2012

LiDAR laser scanners are starting to be mounted on drones too.  It has taken a long time to miniaturize LiDAR sensors to the point that a small-medium sized drone can carry one.  Drone LiDAR sensors to date have not been able to provide classification so that a bare earth model can be produced.

Magnetometers are being mounted on drones too (Pioneer Exploration, GEM).  These are geophysical sensors used to measure changes in Earth’s magnetic field.  This sort of data is used in mineral exploration and location of land mines and submarines. There are many more payloads out there such as air quality sensors or wifi internet repeaters.

8451894_orig

The Communication System

Another important component of a drone is the communication system.  It is technically possible to operate a drone without real time communication since they fly autonomously however it is irresponsible and in most places illegal to do so.  An unmanned aerial system will include some form or radio communication with the operator.  The operator will have a radio link hooked up to a field computer with base station software to program the drone and monitor in during flight.  On board the drone will be some form of two way radio system which will transmit data to the base station as well as allow the operator to issue commands.  Telemetry data received from the drone allows the operator to monitor the flight and make sure that everything is working properly.  Examples of telemetry data are things like airspeed, battery health or fuel level, position and orientation.

Typical radio frequencies that are used are 900 Mhz, 2.4 GHz or 5 Ghz.  Range of a standard system is 5-10 km.  Factors that affect radio range are frequency, transmit power, antenna choice and terrain.  Some drone operators have had great success using directional and helical antennas.  Some helical antenna systems are capable of communicating up to 100km away. Cheaper drones communicate via WiFi (also a form of radio) to a smartphone or tablet.  WiFi range is limited to several hundred meters but can be extended with directional antennas.

HelicalAntenna
Helical Directional Antenna with Tracker

Cellular modems are used in some drones utilizing LTE/GSM networks and can greatly increase the operating range.  Essentially you can fly anywhere there is cell coverage.  Satellite systems are also used which operate on a satellite phone network such as Iridium.  Theses communication systems have virtually no limit on range but have slow throughput and expensive by the minute billing.

All the individual parts of drones work together to execute a flight and achieve the goal of the operator.  New uses are being discovered for this technology every day.  The low price and superior data quality make the UAV a powerful tool for collecting aerial data.   In the coming years we are going to see drones used in more and more industries.  It just makes sense.

 

Check out our drones page to see the drone services provided by WestCoastPlacer.

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Where Does Placer Gold Come From? – Part 3 Placer

Where Does Placer Gold Come From? – Part 3 Placer

Placer gold mining has been practiced for thousands of years with evidence dating back as far as 2600 BC in ancient Sumeria and Egypt.  The technology required is minimal with only a gold pan you can refine gold in a placer deposit.  The word “placer” comes from the spanish word meaning “pleasure”.  Perhaps an allusion to the delight of finding precious metal in a river bank.  The word was spread as gold bearing gravels were discovered in parts of North America colonized by Spain.  In fact the discovery of gold the primary motivation for Spanish explorers to dig deeper and deeper into the newly discovered continent.

Big Al Jig

As we discussed in the part 1 and part2 gold is created in fantastic cosmic explosions.  It has traveled across the universe and made up a small part of the material that the earth formed from.  Tectonic and volcanic forces collected gold in concentrated lode deposits where it can be mined.  The concept of how gold transfers from lode deposits to placer deposits is pretty straightforward.  Rock holding the gold bearing veins or ore is slowly chiseled and broken by weathering and erosion.  The erosive forces of water, wind, and ice transport rock fragments into drainage systems such as streams and rivers.  Gold and other heavy minerals will settle out in areas in the stream where the water loses momentum or creates a trap.  These traps form into placer deposits over time.

Erosion

Placer deposition is driven by gravity.  Gold is very dense, meaning that compared to another substance of the same volume it experiences a stronger pull of gravity.  There are other principles of physics that apply to placer deposition.  The property of inertia is the resistance of any physical object to any change in its state of motion.  Less dense objects require less force to move them and in the case of a stream will travel farther and faster than heavy objects.  Gold has a density that is twenty times that of water and about 8 times the density of sand.  Another factor in the formation of placer deposits is Archimedes’ principle which states that the force of buoyancy on an object is  equal to the weight of the displaced fluid.  This principle was historically used to measure density of gold by Archimedes himself.  As gold is many times more dense than water the force of buoyancy on submerged gold particles is much less than the force of gravity.  So gold in a stream is held in place by gravity and resists movement due to its weak buoyancy and strong inertia.
Nuggets

There are several types of placer deposits.  There are alluvial placers, eluvial placers, beach placers, eloian placers and paleo-placers.  For each type of deposit there are miners who specialize in that type of deposit.  All placer deposits have concentrated gold from its source in some kind of trap.  The vast majority of the placer gold that is mined in the world is of the alluvial variety.

Alluvial placer deposits are formed in watercourses such as creeks, rivers, streams and deltas.  The gold is eroded from lode deposits and carried into the watercourse through rains and melt.  Once into a stream it can be moved great distances.  Gold does not move easily in a stream due to the inertia and buoyancy forces described above.  It takes many years for gold to make its way into a stream and to travel within it.  The gold will move along the bottom of the stream until it reaches a point where the water loses velocity or it is physically trapped.  Typically gold will accumulate on the inside bends of a river where the water velocity is lower.  Large rocks or outcrops can create a natural riffle or eddy where the water slows down and dense material will accumulate.  Waterfalls are another great trap for gold.

Alluvial placers can be broken into several groups.  Flood gold is placer gold that moves during annual floods or other flood events.  Gravel bars and upper sections of stream sediment are where flood gold is usually found.  This type of deposit generally consists of small flake and flour gold since they move more rapidly than nuggets.  Flood gold is actively being deposited and will replenish year after year

StreamSediment

Streambed placer deposits are essentially the same as flood deposits except that they no longer move.  Streambed placers are found in a current watercourse.  These deposits typically consist of gravel that is settled in the stream bed.  To produce a streambed placer you have to mine under the water.  Techniques that can be used are sniping, suction dredge, or diverting the water using a dam such as a wing dam.

The third type of alluvial placer deposit is a bench placer.  Bench deposits are part of the old stream bed before it cut into a deeper channel.  Benches can contain huge amounts of gold if the river carried gold at that time.  A bench is typically flat on top and may appear like steps coming down the valley side.  Benches can be mined using conventional mining equipment since they are usually high and dry above the current river.

OldSchool

Eluvial placer also known as residual placer deposits are formed before any water transportation has taken place.  These deposits form close the source of hard rock gold.  Eluvial placers will contain much large particles of gold than other types because it takes a lot of energy to move large nuggets.  Often quartz will be found with gold still attached in Eluvial placers.  These types of placers are formed by weathering and decay of the host rock that holds gold.  Areas where there is a lot of iron can break down rapidly as the iron oxidizes.  The lighter overburden is generally washed away and unsorted gravel and heavy material is left in place.  These deposits are generally small and very attractive to small miners they also are close to gold bearing veins which can be very exciting.

Beach placers are deposits that occur on the edges of large lakes or the ocean.  The wave action on the beach is the mechanism that concentrates gold and other dense minerals.  Gold can either be carried to the beach by an alluvial system or eroded directly by waves.  A famous beach placer is the deposit in Nome, Alaska which is featured in the TV reality show “Bering Sea Gold”.

CreepSaltSusp

Eolian placers form in areas where wind is the main mechanism of erosion and not water.  Eolian placers are similar to Eluvial placers in some ways, they occur close to the hard rock source, and are poorly sorted.  Wind does a terrible job of moving gold.  In Eolian placers the overburden is swept away by strong winds and leave the heavy ore behind.  They occur primarily in desert regions such as the arid regions of Australia.

The last type is paleo-placer deposits.  These are any of the above placer types that happened a long time ago.  By a long time we are talking about millions of years.  Paleo-placers were once placer deposits but over time they have been hidden and covered in sediment.  There is often no sign at the surface of ancient river systems below.  Paleo-placers can be ancient river channels, benches or sedimentary rock formed from old placers such as quartz pebble conglomerate.  This kind of deposit can amount to huge quantities of gold and make you very rich.  The largest known gold deposit in the world in Witwatersrand, South Africa is one of these.  Over 1.5 billion ounces of gold has been mined in Witwatersrand.  Deposition occurred approximately 3 billion years ago in Witwatersrand, and it is estimated that 50% of all the gold mined on earth came from that deposit.

Witwatersrand

That’s the story of where placer gold came from.  It was created in incredibly powerful explosions from dying stars.  It made up the earth as it formed and was squeezed into concentrated deposits by volcanic processes.  The veins eroded into river systems and hopefully made its way into your gold pan.  Gold’s unique properties of density and its resistance to corrosion and most other chemical reactions allow it to build into the kind of deposits that we can find and mine.

 

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Where Does Placer Gold Come From? – Part 2 Deposits

Where Does Placer Gold Come From? – Part 2 Deposits

In part 1 of “Where Does Placer Gold Come From?” we discussed the origins of gold and how it appeared on earth.  Now we’ll discuss how it moves into mineable deposits.

LodeGoldwide

Gold is spread relatively evenly throughout the crust of the earth at approximate concentrations of 1 part per billion.  To put that into contrast, low grade mineable gold deposits need to be concentrated to at least 1 part per million which is about 1000 times more concentrated than the background.  High grade gold deposits are in the order of 20-100 ppm.  Gold concentrations are usually expressed in grams per ton, which is interchangeable to ppm.

So if gold is evenly spread through the crust how does it become concentrated?  There are several natural processes that allow this to happen and they are all driven by the same force, plate tectonics.  Plate tectonics is the force that moves continents, creates mountains and most volcanoes, and of course earthquakes.  The image below shows the current tectonic plates and their names.

Tectonic Plates

The plates are constantly moving, crashing into each other and subducting, they are pushed by convection currents in the mantle.  In the distant past there have been several supercontinents where all the continents had come together to from one.  Past supercontinents have names like Rodinia, Godwana and Pangea, it is predicted that a new supercontinent will occur in the next 250 million years.

Subduction

At the boundaries of these plates is where the excitement happens.  It is at these areas such as the West coast of North America where volcanic processes squeeze gold into veins.  There are two main ways that this happens.  Orogenesis (mountain building) takes place as the force of two plates hitting each other forms mountains as the edges of the plate buckle and slide.  In the mountain forming process rock is squeezed to the point of breaking and creates fissures and faults that extend deep into the crust.  These cracks allow heated and pressurized water to come up the cracks.

The other way is driven  by volcanoes forming from the subducted plate.  When the edge of the plate is far enough below the surface it re-melts and the newly molten rock builds up pressure.  This pressurized molten rock is what forms the volcanic chains inland from the subduction zone.  As volcanoes form they crack and fissure the surrounding rock and contribute to the same epithermal process.

HotSprings

Imagine the rock as a sponge and when it is squeezed the water is expelled through the cracks.  It is actually the same way that hotsprings work but with more squeezing.  This kind of gold mineralization often takes place near volcanic or geothermal activity such as hot springs or geysers.  When the mineralized water cools it leaves behind the minerals in solid form which we then call a vein.  Typically we are looking for quartz veins.  Vein deposits are often called lode deposits in artisanal miner vocabulary.  Placer miners will often refer to the “mother lode” that is the quartz vein or veins that broke down into rich placers.

 

There are other hard rock gold deposits other than epithermal lodes.  There are Greenstone, volcanic massive sulphides, porphyry and Calrin trend deposits.  All of these depend on volcanism as well and occur in similar ways as described above.  Areas high in volcanoes and seismic activity are good places to look for gold.  The Pacific ring of fire is an area surrounding the boundary of the Pacific tectonic plate.  This area contains 3/4 of the worlds volcanoes and is responsible for 90% of the world’s seismic activity.  In the gold rushes of the 1800’s prospectors envisioned a world wide gold belt.  It wasn’t until the 1950’s that plate tectonics became an accepted scientific theory and decades later we mapped out that gold belt.RingofFireROFdepositsOf course not all gold is found in the ring of fire.  The largest known gold deposit on earth is in Witwatersrand, South Africa.  It is estimated that 50% of the gold mined on earth has come from this mine.  Witwatersrand is actually a huge placer deposit from 3 billion years ago.    In my next post we’ll finally get to the formation of placer gold deposits.  Stay tuned.

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Where does placer gold come from?

Where does placer gold come from?

If you are trying to find gold it helps to know where it came from.

gold-panning

To start with there is only one kind of gold.  Placer gold and lode gold both come from the same place and are made of the same stuff.  Gold is not actually formed on earth it was formed millions of years ago in distant stars.  In large stars, much larger than our sun elements are combined together in their cores through the process of nuclear fusion.  Our sun like all stars runs on fusion too but it does not have enough mass to produce atoms larger than carbon or oxygen.  Larger stars can generate the gravitational force and heat in their cores necessary to produce elements as heavy as iron.  To create things like gold even more energy is required and that takes place in a supernova.


Supernova

When a large star runs out of light matter the fusion reaction is no longer sustainable and the star begins to collapse on itself very rapidly.  The supernova collapse takes place in a matter of seconds.  While the star is collapsing it produces heat very rapidly and explodes in what is essentially a humongous nuclear bomb.  Supernova events are so bright and powerful that they are brighter than then entire galaxy that hosts the star.  This nuclear explosion allows for higher energy fusion reactions that can produce heavy elements like gold.  The explosion also scatters the newly created material over great distances.
SolarNebula

So how did the star dust make it into the mountains and rivers on earth?  When our solar system began approximately 4.6 billion years ago it was a cloud of dust and gas called a nebula.  This nebula was composed of the remains from older stars that had spread their guts around the universe in supernova explosions.  The molecules of the nebula naturally pulled on each other by the force of gravity growing more and more dense.  As the nebula was collapsing in on itself it also started to spin faster and faster.  The condensing and spinning action formed the nebula into a disk, much like you spin dough into a pizza.  In the center where the force of gravity is the strongest a new star was created, our sun.  The swirling mass around the sun clumped together into the planets, moons, asteroid and comets that we see today.
Early Earth

The early solar system was different that it is today.  The big planets did not form all at once, it was a gradual process.  Small plantoids formed first and crashed and coalesced into each other to form larger planets.  In theory the distribution of gold was basically even in all the rocky material that made up the early solar system.  In the early earth, while it was still completely molten the heavy material (such as iron and precious metals like gold) all sunk to the center of the planet to form the core.  The process is similar to the way that dense material sinks to the bottom of your gold pan.  If you could mine the core you would be very rich but it would be very difficult with current gold mining equipment.  Current scientific theories estimate that there is enough gold in the core to cover the surface of the earth with a 4 meter thick layer of pure gold.


earth-core

We can only reach gold that is trapped in the crust of the earth.  The precious metals in the crust were put there by meteor bombardments that took place after the crust had formed.  As these meteorites crashed into the surface of the earth they disintegrated and mixed their material into the upper mantle.  The meteorite guts had the effect of enriching the amount of precious metals in the crust.

 

So we know where gold came from and how it was formed.  Stay tuned for a future post to learn how the gold formed into deposits in the mountains and streams that we mine.

 

Check out Part 2 & 3 here:

Where Does Placer Gold Come From? – Part 2 Deposits

Where Does Placer Gold Come From? – Part 3 Placer

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