Buried Treasure!
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geowizard
17:00:11 Wed
Apr 2 2014
Buried Treasure!

Geophysical anomalies represent potential buried treasure.

That's a fact!

I am actually amazed at the amount of buried treasure in just the Forty-Mile mining district. From Boundary to Jack Wade to Taylor Mountain.

If metal detectors work - and by the way, they do!

AND

If magnetometers find shipwrecks with sunken treasure - yes, again, they do!

Then, Airborne geophysical surveys also find buried treasure!

So, this thread is dedicated to finding "buried treasure".
:smile:

Any questions?

- Geowizard

micropedes1
15:19:34 Thu
Apr 3 2014
Re: Buried Treasure!
Geo, I have put boots on the ground and sampled thru the areas that you have indicated. I also have the geophysical maps of the area, but not the expertise to use them effectively as my background is in chemistry rather than geomagnetics.

Topo maps, geomagnetic highs and lows, helicopter flight lines, fault lines, coplanar resistivity....my walls are covered with maps. Plus assay results, both mine and some of those from big name mining operators in the area.

I have read thru some of your tutorial attempts with us before. Which of the geomagnetic reports do I need to start with?

Rod_Seiad
16:21:01 Thu
Apr 3 2014
Re: Buried Treasure!
Quote: geowizard at 17:00:11 Wed Apr 2 2014


Geophysical anomalies represent potential buried treasure.

Then, Airborne geophysical surveys also find buried treasure!

- Geowizard



That's a rather large leap of faith, don't you think?

Couldn't we agree that, Airborne geophysical surveys find anomalies....:confused:



geowizard
16:40:49 Thu
Apr 3 2014
Re: Buried Treasure!
Rod,

No, we cannot simply agree. Geophysics is based on physics. Not on agreement. The process of understanding fundamental science and physical processes involves measurement of physical properties, verification and repeatability. If we simply "agree" as a matter of blind faith, then someone else might come along and with a different, untested, unproven "science" and you (or we) would simply "agree". So, no, we cannot agree. I can offer physical proof that the laws of physics work and are demonstrated every day by metal detectorists that consistently find gold and other forms of buried treasure. Those electromagnetic systems (metal detectors) work whether we agree or not! :smile:

- Geowizard

geowizard
17:11:04 Thu
Apr 3 2014
Re: Buried Treasure!
micropedes1,

I think chemistry is a relevant background. Since all matter is composed of elements and the combination of certain elements comprise inorganic chemistry, we close in very quickly on metals and their compounds. :smile:

Expanding on metallic compounds and knowing that metals have differing degrees of magnetic susceptibility provides a bridge to the concept of a metal detector and how electromagnetic induction is used to find metals.

The magnetic field of the earth is passive. The magnetic field varies over time and that variation is referred to as diurnal variation. Diurnal variation is the reason why you need TWO magnetometers to conduct a magnetic survey. One magnetometer is placed at a fixed location to measure diurnal variation while the survey is conducted with a second magnetometer. Then, the diurnal variation is subtracted from the survey measurements. That way, the survey measurement shows the actual magnetic intensity of the survey area and not the diurnal variation.

Electromagnetism is not passive. The earth is "energized" by an electromagnetic field. The magnetic susceptibility is now amplified and made larger and easier to measure. All of the metal detectors in use today use the physical properties of electromagnetic induction to measure the amount of metal and mineralization in the earth.

So, the geo-magnetic measurements (passive) are combined with electro-magnetic measurements (active) and together, the measurements can be used to find buried treasure in the form of hidden deposits of gold, silver, platinum, nickel, REE's, iron, etc.

The process of interpretation is important. Interpretation of the geophysical data is complex because it involves an understanding of the physical properties of the rocks and metals and well as the geo-chemistry.

- Geowizard

geowizard
17:29:36 Thu
Apr 3 2014
Re: Buried Treasure!

Resistivity;

Understanding the concept of resistivity is important.

Some people cannot "wrap their head around it".

Resistivity and resistance are physical properties that can be measured. Why is resistivity relevant? Resistivity is related to the amount of conductivity the earth has. The more conductivity we measure, the more mineralization (and conductive ions) there are in the area where the measurement is made.

So, after we wrap our heads around that, then we can begin to formulate a process of interpretation.

Salt water is conductive. Salt water has conductive ions in it and those ions which are predominately sodium (a metal) can cause a lot of excitement. Since we are probably not looking for salt water, we have to apply some interpretation.

- Geowizard

geowizard
17:42:58 Thu
Apr 3 2014
Re: Buried Treasure!

Magnetic intensity;

Different areas have more or less magnetic intensity. Igneous rocks may be more or less magnetic than sedimentary rocks. Rock formations have a "characteristic" magnetic intensity.

We know that magnetite is magnetic. We also know that magnetite MAY be associated with gold!

Since magnetite is often associated with gold it becomes a potential "marker" of a gold deposit.

Normally, magnetic anomalies have intensities of 100 to 200 nano-Teslas (nT) over surrounding areas. Witwatersrand in South Africa produces a 400 nT anomaly.

The largest known magnetic anomaly in North America is at Sudbury, Ontario, Canada. It represents a 9000 (plus) nT magnetic intensity anomaly. It is a rich "buried treasure" composed of Nickel, Platinum and REE's.

- Geowizard



geowizard
17:50:11 Thu
Apr 3 2014
Re: Buried Treasure!

Interpretation of magnetic anomalies;

Unfortunately, magnetic anomalies are not where they appear! :confused:

The reason magnetic anomalies are not where they appear can be demonstrated with a small bar magnet. Hold a bar magnet under a sheet of paper. Hold the magnet at an angle. The magnetic flux points in the direction of the magnet and produces a flux that goes though the sheet of paper at a point that varies according to the angle of the magnet and the distance from the paper. If the paper represents the surface of the earth and the magnet represents the magnetic ore body, then you have a good example that illustrates the problem of interpretation of magnetic intensity.

- Geowizard

micropedes1
21:11:53 Thu
Apr 3 2014
Re: Buried Treasure!
OK. I understand that induced magnetic properties of an ore body are contingent upon the type of metallic oxides present, the particle size, and particle density. And that induced geomagnetic signature is quantitized as either a high or low based upon ambient geomagnetic properties of surrounding formations at the time that the testing was performed.

My question: If there is a geomagnetic high and low that are very pronounced and proximal that extend thru an area of low resistivity (and therefore, high conductivity) might this not indicate a fault zone passing thru an ore body? And if that were true, would not surface sampling and AA mineral analysis of the area in question reveal some identity of the subsurface cause of the magnetic high?

I know...depends upon the shift within the fault, if there is actually one there.

micropedes1
21:20:13 Thu
Apr 3 2014
Re: Buried Treasure!
At least one of the anomalies that you indicate has been identified as a Zn/Pb/Ag reef with small amounts of free gold. It is extensive. The problem is that it is too deep beneath the surface for me to be able to reach. And its depth makes it an unlikely source for all the existing placer gold in the 40 Mile today. But, who knows what mineral enriched grounds have been eroded away and redeposited in that area since the original emplacement!

geowizard
00:36:28 Fri
Apr 4 2014
Re: Buried Treasure!
micropedes1,

That's good news!

The mineralization probably outcrops or comes near to the surface somewhere along strike. This is where the chase begins. trenching along strike will reveal near surface mineralization and possibly the "pup" that cuts across the mineralization. My experience is that nature has done much of the excavation. We merely have the challenge of following the mineralization to the point where it reaches the surface.

Also, because the forces that push mineralization from deeper lodes vary along the strike of a fault, the fault will contain more near-surface mineralization. Faults may pinch off the ore in one area and open up in others.

Yes, it is an analytical process.

- Geowizard

baub
00:19:30 Sun
Apr 6 2014
Re: Buried Treasure!
Good thread.

b

geowizard
15:14:35 Sun
Apr 6 2014
Re: Buried Treasure!
Thanks baub!

The first rule in looking for buried treasure is to know who owns the buried treasure! :confused:

You don't want to go through all of the effort to find buried treasure to find out someone else owns it.

Let's go look for buried treasure around Jack Wade Junction in the Fortymile mining district.

First, you need a treasure map...

Here's a view of the area provided by Alaska Mapper that shows the area we're interested in and where the mining claims are:




Here's a view of the geology:




Courtesy of Alaska Division of Geological Surveys pir2002_001a_sh001.pdf

Stay tuned... :smile:

- Geowizard

geowizard
15:31:12 Sun
Apr 6 2014
Re: Buried Treasure!
So, we park our car next to the road at Jack Wade Junction. We load up our back pack and proceed west along the trail to an area shown in tan color that says pMsg.

Here's a description of pMsg:




Courtesy of the same reference above pir2002_001a_sh001.pdf

Off to the left as we walk along, is Qh. This is Quaternary placer tailings (a possible clue).

Note that the mapper image shows placer (gold) mining claims (blue squares). The area outside of the blue squares is open for location of mining claims.

The trail continues along the top of section 7 and then turns south between section 7 and 12 toward the north east corner of section 13.

There is a contact of pMsg, and Mog with pMa. All of these rock types have lengthy descriptions for those interested.

Stay tuned... :smile:

- Geowizard

geowizard
20:11:28 Sun
Apr 6 2014
Re: Buried Treasure!

If you want to learn more about Mineral Oriented Geologic Mapping of the Fortymile Mining District, here's a start:

http://137.229.113.30/webpubs/dggs/nl/text/nl2000_003.pdf

As we continue our walk along the trail across section 7 and down along the section line that joins section 7 and section 12 and referring to the following close-up of the geology;



We note several additional rock types:



and...



From the geologic map, we can see there are several faults located on the trail at the north-east corner of section 13.

I wonder if there's any buried treasure here? :confused:

Stay tuned... :smile:

- Geowizard

geowizard
23:33:15 Sun
Apr 6 2014
Re: Buried Treasure!

The geology shows "contacts" between different rock types and faults. Mineralization is often found on these types of geologic structures.

Map symbols:




In 1998, a geophysical survey was conducted over the Fortymile Mining District. Between August 18th and September 10th, an Aeropatiale AS350B2 turbine helicopter flew 4753 lines miles at 94 miles per hour and 100 feet above the ground. It measured two anomalies in the immediate area.

Anomaly 1; with a Conductivity-Thickness product of 57.6 and depth to top of 60 meters.

Anomaly 2; with a Conductivity-Thickness product of 52.9 and a depth to top of 51 meters.

From the north-east corner of section 13, the vector to anomaly 1 1563 feet at 273 degrees. The vector to anomaly 2 is 900 feet at 191 degrees.

Over millions of years, buried treasure has been pouring into Robinson Creek. So, even though the ore bodies are deep, the gold has reached the surface and through erosion, it is finding its way to surrounding bedrock.

The next step is to call my uncle Vinny in Chicago for a loan. :confused:

Next, I will discuss how to recover the buried treasure.

Stay tuned... :smile:

- Geowizard

hoppingforpay
05:21:53 Mon
Apr 7 2014
Re: Buried Treasure!
With a Bobcat?

geowizard
14:06:55 Mon
Apr 7 2014
Re: Buried Treasure!
Access to the location is along the Jack Wade trail. The trail goes through deeded ground. An easement and 25 ft wide right-of-way was reserved for public access.

The shortest path to reveal the mineralization is to core drill the anomaly.

One option is an Atlas-Copco core drill.

http://www.atlascopco.us/usus/products/navigationbyproduct/product.aspx?id=1515248&productgroupid=1460180

This is a towable, self contained core drill that can drill to 2000 feet.

Although the top of the anomalies are between 167 and 196 feet, the mineralization can be expected to be near surface. The surface area consists of a mineralized halo. So, as core drilling is conducted, the drill will encounter increasing mineralization with depth.

Although core drilling is exploratory, we do have knowledge of the fact that an anomaly exists and the cards are stacked in our favor. Knowledge of the exact location of a mineral deposit improves the probability of intersecting mineralization.

I know of cores that intersected gold mineralization in Alaska that after analysis, in one case, the core was sold for $70,000. That funded further drilling and development of the deposit.

There are examples of core drilling of kimberlite pipes in Labrador that intersected gold mineralization - all of the drilling was based on known geophysical anomalies.

The process of core drilling can be improved through the use of ground geophysical methods. One method uses electromagnetics to energize the area surrounding a deposit while lowering a receiver into the drill hole. This process increases the definition of surrounding zones that contain conductive mineralization.

Stay tuned... :smile:

- Geowizard

geowizard
14:45:43 Mon
Apr 7 2014
Re: Buried Treasure!

With reference to core drilling, 200 feet is shallow.

There is no shortage of options for drilling equipment. Here's another option:

http://www.ardco.net/products/geophysical/

The process of drilling should be done at leisure. In order to effectively drill a deposit, time should be taken to collect cores and properly document and box the cores into core boxes. I also collect the cuttings from the core drill for assay. If holes need surface casing to avoid collapse of the hole, then casing should be used. Drill holes provide a resource that can be used for future mining. If underground mining takes place, drill holes can be used as pilot holes for shaft sinking.

Stay tuned... :smile:

- Geowizard

geowizard
15:02:11 Mon
Apr 7 2014
Re: Buried Treasure!
Light-weight exploration drills are available. In remote locations, it is sometimes necessary to lift drills by helicopter to the drill site.

http://www.mining.sandvik.com/

Sandvik Mining has portable exploration drills designed for remote areas.

Next, I will discuss the process of selecting the mining method.

Stay tuned... :smile:

- Geowizard

geowizard
14:06:49 Tue
Apr 8 2014
Re: Buried Treasure!

Exploration drilling is used to define the deposit.

Definition of the grade and extent of the deposit allows a miner to forecast the financial return on investment and to budget cost of mining while predicting revenue. The cost of exploration drilling is minimal compared to the cost of sinking a shaft. Exploration drilling can continue at the same time a shaft is being sank. The shortest path to the deposit is a vertical shaft. Since there must be a local outcrop of gold bearing mineralization (as evidenced by placer gold in Robinson Creek), it is prudent to look along the west slope of the hillside. Geo-chem sampling by trenching or augering could lead to the discovery of an outcrop.

The first objective is to be able to mine into the deposit and produce revenue during the process of mining. Otherwise a cost analysis of mining versus return on the investment becomes a necessary part of the work to be done. The importance of planning on the cost of mining cannot be under-estimated. With adequate definition of the deposit from exploration drilling, and news of the discovery, funding opportunities will present themselves. Gold miners that have producing mines often are self-funding.

The preferred approach to mining as relates to shaft sinking, is to contract the mining to a shaft sinker. Shaft sinkers work on contract. They take care of their own personnel, are insured and bonded. Details related to construction of a head frame and collar are managed by the shaft sinker. If an outcrop is discovered on the west slope, an adit can be driven directly along mineralization to the deposit. One of the anomalies appears west of the crest. It is possible that an outcrop already exists. Adits are driven into deposits under contract by contract mining companies.

The buried treasure must be sorted.

That's another way of saying that the deposit may be poly-metallic and the valuable components need to be separated. Two options are apparent. Mill and concentrate on site or transport to another location for milling and concentration. the cost-benefit is calculated for both options.

The Fortymile mining district has thousands of placer deposits. The district has thousands of lode deposits. Each of these lode deposits represent an opportunity for miners to get busy. Over the course of time - looking forward, more areas will come under mineral closing orders, become wild and scenic areas or otherwise be removed from mineral entry.

- Geowizard

geowizard
15:09:19 Tue
Apr 8 2014
Re: Buried Treasure!

Big nugget or little nugget? :confused:

Metal detectors respond by producing a signal. The signal is proportional to the conductivity of the target.

Little nugget = "Wheee!"

Big nugget - "WHEEE!!!"

A world class deposit is classified as a deposit that has a conductivity-thickness product greater than 100. They are referred to as Grade 7.

The next lower grade is Grade 6. Grade 6 anomalies have a conductivity-thickness product of 50 to 100.

Both of these targets are Grade 6 anomalies.

This grading system is based on current producing mines and their response to the geophysical survey system employed in this survey.

Is it magnetite?

Magnetite is magnetic. The system that was used in the discovery of this anomaly contained a calibrated Cesium vapor magnetometer and a second magnetometer reference station to eliminate diurnal variation.

The magnetic response was 14 nT (very low). Surrounding levels were greater.

All of this indicates noble metal mineralization with surrounding increasing levels of magnetite.

- Geowizard

geowizard
16:33:43 Tue
Apr 8 2014
Re: Buried Treasure!

The Mattabi deposit, Sturgeon Lake, Canada is an example of a Grade 6 deposit.

Sturgeon Lake is now a past producer.

It produced 2.1 Mt (Million tonnes) of 2.98% copper, 10.64% Zinc, 1.47% Lead, 6.14 opt silver, and 0.21 opt gold.

Gold production was 4410 ounces.

Silver production was over 12 million ounces.

10 percent copper = about 200,000 pounds.

A Grade 7 anomaly was Montcalm nickel-copper, Timmins, Ontario, Canada. The Kidd Creek Proven and Probable reserves are 19 Mt of 1.8% copper, 5.5% zinc, .18% lead, and 53 gpt silver.

http://www.mining-technology.com/projects/kidd_creek/

These are examples - your results may vary! :smile:

- Geowizard

hoppingforpay
02:25:03 Wed
Apr 9 2014
Re: Buried Treasure!
If you head due North you run into this claim block.

http://www.millrockresources.com/projects/fortymile/

A friend of mine (I have them in real life) staked some of what turned out to be some of the better ground. Twice he declined offers from Teck and perhaps Millrock,I'm not sure. The last offer was seven figures. He has held these claims for 14 years. It gets spendy to do this...hopefully he gets more offers.

Napolean Creek has good gold down by the South Fork but it disappears as you head up the creek to what may or may not have been the source. This is evident by countless prospecting shafts in the creek but no workings. Maybe it was high standards just not enough..

Their was some gold on Robinson at the mouth but apparently it disappeared to the operator when moving up the creek.

I walked up it a ways and it looked like the old timers left it alone. I didn't go far up the creek because I wasn't that interested in it because the creek is too small for what I was doing. There might be something on it but if so it is probably in discontinuous streaks that would baffle and lesson it's value. and the interest of knowledgeable heavy equipment operators.

One must also consider when using geophysical maps and what not for placer, is all the other variables not on the map.Like the whole mountain that eroded before the survey, the grade of the stream,the old timers. Their were lots of miners in the Jack Wade valley and they no doubt went up and dug holes on all the side creeks to bedrock. Is there gold on some of these side creeks? Probably, but being coarse gold country the best and cheapest way to find out is to camp out, melt and dig holes to bedrock. Not too many prospectors doing this. You could use a metal detector but these have better results in ground that has been torn up by equipment. Seldom is the bedrock close enough to the surface in undisturbed creeks to ever get a metal detector close enough to get a nugget reading. You would want to use a pan anyway to assess ground because specks count if you are able to find shallow bedrock.

The old timers miss ground on occasion but looking at ground they ignored is more risky for returns than going someplace that they actually hand dug gold out.

Most of the mining claims in Ak are pretty much worthless, if I were to guess I would put the number around 97%. Most claims are just claims around someone elses claim who is around someone elses claim and on and on it goes....I believe somewhere around 45,000 claims this past year were filed.

So do the maps show something at the mouth? There was a buried treasure there...

Good day gentlemen it's been real (sort of) and fun but not real fun! Carry on!

geowizard
14:55:03 Wed
Apr 9 2014
Re: Buried Treasure!

With reference to Millrock Alaska;

Here's an overview of their Fortymile project:

http://millrockresources.com/projects/fortymile/

Millrock uses a "Project Generator" business model. They recognize the important contribution made by geophysics and follow-up drilling.

The Fortymile is rich in buried treasure. The old-timers used the tools they had to explore for gold. They were successful in finding much of the gold that was in obvious localities. Gold eroding into creeks and streams is a "no brainer". Digging holes and panning gold are skills that can be learned in less than an hour.

Metal detectors have added a new dimension to prospecting for gold. The technology applies to airborne geophysical surveys. Scientists at Alaska DGGS are involved in continued surveys of the mining districts in the state. Millions of dollars are being spent every year to define new mineral deposits.

There is a window of opportunity for prospectors!

Interpretation of the data is showing me that mineralization is present that supports known and some unknown placer gold deposits. Many of those deposits remain unclaimed. These geophysical anomalies offer an "opportunity" for prospectors to get on a mineral deposit that is supported by geophysics.

The probability of success is much greater digging a hole looking for gold when a metal detector has indicated the exact location to dig. It is unfortunate for miners of the past that did not have the technology.

- Geowizard

Scrub
18:30:19 Wed
Apr 9 2014
Re: Buried Treasure!
Most of the areas mentioned are either claimed or unavailable. If it's not already claimed, it's Doyon, BLM or other Federal. Doyon is no longer accepting applications for placer mining. Federal is tough due to the restrictions too inumerable to mention in this blog.

Is it even legal to prospect on Doyon & BLM w/o a permit?

Muley
01:33:53 Fri
May 9 2014
Re: Buried Treasure!
Geowizard,
Fantastic presentation on the value's of using modern technigues for prospecting, I plan to read it again.
As far as portable drill's go, be careful not to go too light and end up bouncing on the rock instead of cutting through it.

geowizard
03:35:03 Sat
May 10 2014
Re: Buried Treasure!
Muley,

That's good advice.

I use drills that I can keep at least 7000 lbs of weight on the bit.

Thanks!

-Geowizard



Buried Treasure!
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