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flintgreasewood

2016 At Cobb

21 posts in this topic

A
few months ago I was frustrated with my inability to get anywhere with
the old Cobb prospect shaft.  Between then and the end of 2015 I fiddle
farted around with reconfiguring my steam system and making my work
shacks semi habitable in the extreme cold that was to come.  When the
temperatures here in the interior of Alaska insisted on staying well
above 0 it came into my head to put down a new shaft.  Earlier in the
year I had carefully walked the area directly downstream from the old
shaft looking for possible sites.  Though the ground was now covered
with 2 feet of snow I easily relocated the chosen spot.  With my trusty
aluminum scoop shovel I removed the snow from a large area and went at
the frozen moss and brush with a pick adz.  Darkness crept in slowly
even though it was only 4:30 so I ran a 100' extension cord
from the camp, set up my flood lights and worked on into the
night. 


    Integral to a new shaft would be a new gin pole and I figured I'd
have to cut down a large spruce, drag it a couple hundred yards,
jackhammer out a pit in the frozen ground and rig up a hoisting system
to raise it up in place.  The prospect of all that work caused me to
rethink the positioning of the gin pole and it hit me that I merely
needed to run my highline to the tallest, sturdiest spruce 90 degrees
from where I had originally thought to place it.  I wouldn't need a
pole that would have to be in service for many years...just a year or
two.  And if I needed something more substantial later on I could take
care of that in the spring.  I found the right tree, brought in my 18'
ladder and proceeded to position eye bolts and guy wires for support.The
high line would need to be anchored behind the shaft and to do that I
had to dig a pit in which to set a "dead man".  However. the angle of
the high line over the shaft area would be too low to allow a bucket to
exit and clear the shaft wall.  I had to rig an elevated support, a
"quad pod" of spruce poles between the anchor point and the shaft that
effectively raised the high line 5' above the shaft.  I'll have to hang
the bucket to determine if the high line is elevated enough.  Once I had
the high line in place I could begin filling the dead man pit, but with
what?  I didn't want to use frozen muck with its high water content.  I
opted for gravel and the best and closest source for that was the pit
we've been slowly excavating for our outhouse.  Of course that gravel
would be frozen so I loaded up the generator, jack hammer, shovels and
weed burner in the sled and zipped on up to the cabin.  The jack hammer
doesn't work properly when it's cold and that's where the weed burner
comes in.  I spend a few minutes warming up the jackhammer and my gloves
and everything works much nicer. I underestimated the amount of gravel I
needed to fill the dead man pit and had to return for another load.  To
insure a strong dead man I dumped in 10 gallons of water to freeze it
into one solid block.
   Now I'm working on an electric hoist and as
soon as I can get it operational I'll be able to begin actually digging
out the shaft.

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Dick

At the new shaft probably 60' of muck. Since I'm working alone I need a system whereby I can get the muck out and away from the shaft without having to climb a ladder each trip. Unfortunately I am working on such a tight budget I can scarcely afford even the smallest expenditure. I am often forced to do every task with just my hands and simple tools much the same as the first miners in Alaska. In some ways I don't mind that as it gives me a connection to those hardy souls. But I'm also getting old enough that work of that sort takes more of a toll than it did 10 years ago. without havi

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Are you planning to pick through 60' of muck !?!  That is my least favorite part of winter shaft sinking.

Fortunately I only have had to deal with 10-12' of muck at most so far.

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I have a 40lb electric jack hammer that breaks up the muck very nicely.  I just found a good used motor in Anchorage and as soon as I can get it here I'll get the hoist up and running and start digging.  The weather is cooperating nicely and I'm optimistic that we'll not be having any super cold this winter. 

   Why do you dig shafts?

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Kurt,

  I like the electric jack hammer idea !

I sink holes for prospecting. Never did any serious drifting in any of them.

Over the past 40 winters I've been here in the Fortymile I have probably sank 

close to a hundred holes on various creeks in the area.

 Here is one I was working on a couple years ago. This one ended up being abt 26' to bedrock.

 

stonehouse%20shaft.jpg

Ronald C likes this

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Dick,

That's quite the ambitious shaft sinking. How often have you hit good pay without drifting?  How do you remove the muck once you can't pitch it out?  The jack hammers I use I got off ebay, the inexpensive Chinese ones.  I have 2, one for backup and have been more than pleased with them. 

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Kurt,

 Yes I've hit some real good pay at times.

Keep in mind none of my sinking has been near the depth your doing.

I'd say my average shaft was less than 20'.

 I just used a 5 gallon bucket and rope. Never bothered putting up a windlass

until it was at least 20'.

 

 That's changing though with age. Pulling up a 5 gallon bucket full of wet slop

ain't as easy as it use to be ! 

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Dick,

Are you currently putting down a shaft or will you start one this winter?  If you're interested I can draw up a simple dumping system that I came up with when I removed all the ice from my shaft.  It allows you to work down in the shaft and dump a bin full without coming up every time.  You would probably have to come up every five or six trips to keep the trough clear. 

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 Yes I am. Cleared out a spot last Fall. Not going to start on it until mid Feb. Don't anticipate it being much

more than 15'.

 Thanks but I like it keep it simple. Bucket and hand-crank windlass suits me fine for what I do.

 Good exercise going up and down the ladder :D !

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As Jack Nicholson declared in
"The Shining"..."I'm back!!"  Finally I have some real progress to
report on.  It was early January when I began my new shaft at Cobb
Prospect. Most of my efforts then were done in darkness and below 0
temps but the excitement of a fresh start kept me on task.  Now it's
nearly spring with lots of light and often above freezing days. 
Actually, nearly the entire winter offered more than bearable and often
downright pleasurable working conditions.  Setting up my electric hoist
was not a simple matter; should I have expected different?  The hoist
came with a 3/4hp DC motor and controller.  The motor was good but the
controller wasn't, so I gave up and switched to a 1hp AC motor I found
on Anchorage Craigslist.  It fit the speed reducer fine and it looked
like I was in business but when I put the juice to it the generator
struggled and the motor barely spun.  Being somewhat ignorant of many
things electrical I succeeded in letting the smoke out of the motor. 
And as everyone knows, motors are run by pre installed smoke at the
factory.  When that smoke gets out the motor quits working.  Simple!  I
brought it in to the local motor repair shop and to my relief I had just
burned out the capacitor.  But I also got the news that my generator
was under powered.  A friend said he had a 4000watt out at his mine site
that I could borrow so we made the 50 mile trip out [ran out of fuel on
the way] and the next day I hauled it down to the prospect.  I should
have paid more attention to the motor technician.  A 1 hp motor requires
4400 watts for initial startup.  The replacement didn't cut it.  I
didn't have the funds to plunk down on a new 5500 watt machine even a
cheap one from Lowes but I applied for and received one of their cards
and was able to get it on credit.  The one I picked was marked way down
as it had been bought and returned because it was too small.  It was
also a propane only model but I figured I could get along with that. So I
hauled that one down, unpacked it and read the owner's manual.  When I
saw how much propane it would consume in a 4  hour run time at 50% power
I was stunned.  I'd have to spend at least twice what I would have to
with a gas model.  I packed it back up, returned it, picked up a gas
model and hauled it down to Cobb.  My plan was to control the hoist with
a cheap reversing drum switch I had used in the old shaft.  The wiring
was more complicated with the new motor and it took me hours of analysis
to figure out how to set it up.  It didn't work, most likely corroded
contacts.  I was fed up and went searching for an industrial grade
switch, found one on an Ohio craigslist and bought it.  In the interim I
wanted to use the hoist as I was now deep enough in the shaft that it
was getting too difficult to pitch the frozen chunks of muck out by
shovel.  I realized that I could operate the winch by simply making a
setup where I would have an on/off switch and two terminals that would
allow the swapping of the reversing wires fit with alligator clips.  It
worked. 

   I wanted to use a standing live spruce for my gin pole and had
available but one that was tall enough   I soon realized that the angle
of the carrier high line was too flat between the head frame and the gin
pole.  For a temporary solution I erected another gin pole mid point on
the line which provided a steeper slope which would allow the bucket to
generate enough momentum on it's return to trip the release catch. 
That didn't help.  Next was to increase the hoist speed by doubling the
drive gear pitch.  The additional speed and reduced trip time was great
but still wasn't fast enough for the bucket to release.  I noticed that
if the bucket dump chain got caught and held the bucket still for even a
couple seconds, enough slack in the hoist line was generated so that
when the chain was loosed, the bucket ran free with enough speed to
release at the trip pin. I rigged up a catch point using a plastic
barrel placed under the trip line.  That worked...most of the time, but
not all the time.  Adding more weight to the bucket didn't seem to
help.  What next to try?  I checked the carrier for possible issues and
found an obvious problem .  A retracting spring was too stiff and held
the catch mechanism too firmly in place for the trip pin to move it. 
Changing the spring helped but still didn't completely solve the issue. 
I removed the carrier, took it home removed just one side plate so I
could manually operate the various parts, something I had never done
before.  It was easy to see that a bad angle on one of the catch pieces
made it very difficult for it's mating part to slide off to allow the
bucket to release.  Those fixes helped even more but I'm still not quite
satisfied; I need the bucket to trip every cycle, not just 90% of the
time.  Since I was not happy with my gin pole setup, I decided to erect
an even taller one next to the original and using that one to hoist the
new one in place.  Using my chain saw winch I dragged the 28' black
spruce down the hill through 2' of snow, reattaching three times to make
bends in the route through the standing trees.  That was, by far the
hardest part of the job.  Hoisting the new pole required that I work
from a ladder propped against the old one.  A number of guy wires
connected to spruces with ratchet straps and turnbuckles were already in
place including the main carrier line and all had to be loosened, some
removed and repositioned and retightened numerous times. In time I was
able to separate the two poles held together by straps and cut the old
one down, leaving the new, bigger and taller one standing alone.  More
wire adjustments brought it straight and true.
 
  I  had managed to dig the shaft down to 8 feet [that's 8'x8'x8']
and it was time to put in the cribbing.  During February I began
harvesting large black spruce, cutting them into 8' lengths, carrying or
dragging them through the deep snow to a sled. I was able to stack 8 or
9 of them to be hauled behind my snow machine down to the shaft site.
As I prepared to start setting the logs I could see there was not going
to be space enough for the bucket to ride up and down the shaft freely
with a cribbed wall.  Evidently I would either have to enlarge the shaft
on the one side by at least a foot, or move the gin pole.  I almost
couldn't bear the thought of another gin pole change, but the thought of
jack hammering and  removing an additional 3+ cubic yards of frozen
muck was even more unpalatable.  I knew the gin pole was setting not in a
deep hole but merely just below the moss on frozen muck.  If I cleared
out a path through the snow and moss, I could put a comealong on the
pole and simply drag it to the new spot 5' away.  I just had to keep
adjusting tension on all the wires supporting the pole.  The entire
operation took less than 3 hours and went without a hitch.  Amazing!  I
now had plenty of room for the bucket to operate. 

    Cribbing began with placing two over length base logs in place. 
To accomplish that I had to jack hammer notches in the walls at the
bottom of the shaft. Sounds easy?  It took more than half a day to get
them set and I was whooped.  Successive log courses went in relatively
smoothly and I'm now up to just over half way to the surface. At the 4'
point I began placing glass wool insulation between the walls and crib
logs which are set to make a 6' square shaft.  So that's where things
stand.  Oh, I did receive the new drum switch and found it had a part
missing that kept it from reversing.  Just yesterday I made that part in
the machine shop where I am doing temporary contract welding.


 



                



            



        







        


            


                


                    


 








 



                



            



  






        


            




 


 



                



            



        







        


            


                




 



                



            



        



    



 





                



            



        



    



 

 


    



 

 
     



    



 

 


    



 

 

 

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Kurt,

Glad to see you back buddy, I had really missed your updates.  Sounds like you had a productive winter and I'm happy to hear you are making progress.  Keep up the good fight.....oh yeah, be careful as well!

 

JR 

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Here's a brief update on my work at Cobb prospect this season.  I'm now down to the 40' level in my 6x6 shaft.  It hasn't been easy with problems of spring snow melt, a snapped gin pole, endless modifications of the hoisting system. trails turning to mud bogs. dying jack hammers and just plain gettin' older and tireder.  The gin pole situation was nearly fatal as it allowed the full bucket to be free to return to the shaft and fall 25' to land right at my feet...a real heart stopper.  God is good and saved me from harm.  I now have a full size 2" x 10" x 10' plank that I used as a shield every time I hoist or lower a bucket.  Don't wish to put God to the test again so soon.   Then I had to cut and drag into position a new and larger pole to replace the broken one.  Raising the 34' spruce with tripods, come along, a small electric winch and lots of guy wires was no easy trick, but I managed.  The trail turned bog forced me to find a new high and dry route to the prospect but that entailed crossing Vault Creek and two little pups.  To do that I had to build three bridges, two of them 30' long and one 10'.  That's a lot of 4" x 4' poles.  While pitching some of those poles I threw out my back and an MRI determined I ruptured a disc in my lower back.  So I've been limping around for 6 weeks with a numb foot [pinched nerve] and am awaiting laser surgery in late Aug.  Fortunately, I am not in pain and can still work in the shaft as normal.  I now have all systems working to near perfection with a new jack hammer and even a small hoist dedicated to hauling me up and down the shaft instead of having to use the ladder...a real energy saver. Just the other day I noticed my bucket refused to lower into the shaft.  I determined the dead man that was anchoring the main high line was giving way so that the line was too slack.  Fortunately, I had several 3 1/2 foot lengths of 1" rebar that I had ground points on. I drove three of them in line 3' apart and connected them base[ permafrost frozen just below the moss] to top and attached the high line to the first one.  It has so far proven to be a fine dead man setup.  I made sure the posts are well insulated and protected from possible rain.

   It's been a lot of hard work and sometimes discouraging  with the slow pace I am going but I'm learning patience.  I have only 16 to 18 feet to go to hit gravel and then things really get exciting.  I'll let you all know when I get there. Till then, have a great rest of the summer mining season.

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For those who have been following my odyssey some real progress has been made on my new shaft in the past two months.  It's been one hard slog to jack hammer my way down to 55' but persistence is paying off.  I'm now in mixed gravel and muck and will be into some gold in a few more feet.  The gravel is proving to be more difficult to jack hammer than I had hoped though it varies around the shaft.  Some will be almost dry and breaks up easily and other places it will be as hard as concrete.  What keeps things interesting though is the fossil remains I'm uncovering.  Just today I pulled out a mammoth metatarsal [toe bone].  Last week I chipped out a 5 lb. chunk of mammoth tusk.  It's likely I'll be finding full tusks as I drive the drifts.  Hoisting is going quite well though I have to watch the weight in the bucket as the gravel is substantially more heavy than the muck and my motor overheats if I overload or send up a bucket without letting the motor cool down a bit.  I'm getting ready to run some heavier electrical wire so that should help with voltage drop.  We'll be building a new boiler house shortly and setting up the steam system though we may be experimenting with some different methods of thawing.

More to come soon.

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