**ICE**

[Armchair detective]

Something we've been overlooking.

In the winter temperatures get below freezing on OI. An open shaft should have ice at the bottom.

Digging in such conditions in the Yukon requires using fire to melt the soil, which might explain the soot marks on the shaft sides.

Note that this might be the way to shut off the flood tunnel.

Just dig in winter.

 

[Armchair detective]

Also when digging for gold you look for ancient riverbeds in the bedrock where gold gathers.
Bedrock at OI is approximately 170 ft, which means the original MP shaft must have been much deeper than 90 - 100 ft.

 

[SSR]

Ground temperature at 100ft depth is in the range of 50-60 degrees F. The surface temperature in this part of NS is hardly cold enough to maintain an ice rink for more than a couple of weeks per season. The average daily high for Halifax in January and February is above freezing.

 

[pepperj]

Every homestead had a well of sorts.
They were able to get water during the winters.
Tge rule of thumb is a Maximum depth for any freezing is 4 feet from ground surface, the coastal waters it's a lot less.

You're theory on freezing the intake of water-debunked.

 

[Armchair detective]

The limited weather information I have suggests that Oak Island runs about 10 degrees cooler than NS (at least in the summer), thus winter's average high would be 23 degrees.

Granted that the deeper you go into the earth the warmer it gets, but that's not the case with an open shaft.

Cold air SINKS. It will be just as cold at the bottom of that shaft as your outside air, unless you cover it.

 

[Limitool]

Cold air SINKS. It will be just as cold at the bottom of that shaft as your outside air, unless you cover it.

True.... but just to a point. The bottom of the pit would be surrounded 360 degrees by warmer earth and any ground water. That ground water/moisture holds a lot of heat especially at 100+ ft. I believe it would never get cold enough to ever stop any water flow. It would act like any common well.

 

[pepperj]

The limited weather information I have suggests that Oak Island runs about 10 degrees cooler than NS (at least in the summer), thus winter's average high would be 23 degrees.

Granted that the deeper you go into the earth the warmer it gets, but that's not the case with an open shaft.

Cold air SINKS. It will be just as cold at the bottom of that shaft as your outside air, unless you cover it.

So what's your experience, (or have lived in one) with colder climate regions.

 

[SSR]

The limited weather information I have suggests that Oak Island runs about 10 degrees cooler than NS (at least in the summer), thus winter's average high would be 23 degrees.

Granted that the deeper you go into the earth the warmer it gets, but that's not the case with an open shaft.

Cold air SINKS. It will be just as cold at the bottom of that shaft as your outside air, unless you cover it.

No. The Earth is a massive heat source emanating from its core. Ice forms at the surface of bodies of water, because heat is lost there. In the contact boundary zone between water and air is where energy is lost. This is a cooling down process of water molecules. Ice forms first a the surface and a gradient forms downward. It is not the case that convection currents of cold water will exhaust the Earth's inner heat. The deeper you go the warmer the planet is.

 

[Armchair detective]

Folks, think about how permafrost works WITHOUT a shaft.

Cold air removes the heat from the earth, the water in it freezes. The longer this goes on, the deeper the ice layer. There is a point where the heat from the core is matched by the heat drawn off by this process - this is equilibrium ON THE BOTTOM SIDE.

On the TOP side, spring comes. Ice melts from the top down. At this latitude, it looks like the whole layer is melted with a yearly repeating cycle.

With an open shaft, the process happens SIDEWAYS, which also answers how you can dig that deep without cribbing.

 

[SSR]

Folks, think about how permafrost works WITHOUT a shaft.

Cold air removes the heat from the earth, the water in it freezes. The longer this goes on, the deeper the ice layer. There is a point where the heat from the core is matched by the heat drawn off by this process - this is equilibrium ON THE BOTTOM SIDE.

On the TOP side, spring comes. Ice melts from the top down. At this latitude, it looks like the whole layer is melted with a yearly repeating cycle.

With an open shaft, the process happens SIDEWAYS, which also answers how you can dig that deep without cribbing.

You don' t have cold air on the South Shore. The ocean moderates the winter temperature. This area of NS is barely above freezing most of the Winter. Permafrost is a remnant from the last glaciation. It's slowly vanishing. It is not an ongoing process.

 

[SSR]

The limited weather information I have suggests that Oak Island runs about 10 degrees cooler than NS (at least in the summer), thus winter's average high would be 23 degrees.

Granted that the deeper you go into the earth the warmer it gets, but that's not the case with an open shaft.

Cold air SINKS. It will be just as cold at the bottom of that shaft as your outside air, unless you cover it.

The ocean water has the opposite moderating effect in Winter. It keeps us 1-3 degrees warmer than inland here. Summer is naturally cooler on the shore.

 

[BuzzMarshall]

On a different note... If the groundwater at around 100ft was froze as some suggest then the idea of Water/Ground Source heat pumps that you can find all over North America would never work... The fact we know that ground water in our neck of the woods is somewhere around 60F is what allows a ground source heat pump to actually work.

 

[releventchair]

 

[Armchair detective]

This is true. Those installations are a bore hole for the pipe size and (I assume) sealed at the top. Air would never get the chance to circulate "down there".

As to whether ice could actually form at the bottom of an open shaft, also note the chimney effect, whereas cold air flows down close to the walls and hot air rises up the center of the shaft, making a constant air circulation.

Ice there year round? Nah.
Ice never there? Nah.
Ice there if you cover the hole? Nah.

Also, mea culpa. Don't know where I got the idea OI is about 10 degrees cooler than NS, nothing supports that.

 

[releventchair]

This is true. Those installations are a bore hole for the pipe size and (I assume) sealed at the top. Air would never get the chance to circulate "down there".

As to whether ice could actually form at the bottom of an open shaft, also note the chimney effect, whereas cold air flows down close to the walls and hot air rises up the center of the shaft, making a constant air circulation.

Ice there year round? Nah.
Ice never there? Nah.
Ice there if you cover the hole? Nah.

Also, mea culpa. Don't know where I got the idea OI is about 10 degrees cooler than NS, nothing supports that.

Expect a 4 foot foundation requirement in order to be below the frost line.
Then look up specific area building codes.

I posted a lot about well digging prior. Likely on one of your posts.
Burning paper used to reduce gas in a hole has been done.
Fire in an occupied well sized hole?

A. It would consume already reduced oxygen you'd want in order to breath.
B. What would your recourse be if you caught fire?
C. What if a tunnels frozen walls are too wet a clay or other saturated substrate when dug frozen and you then add more fire?

Well pits zone 5. Do they freeze?
New zoning doesn't allow them in my area. But I used more than one. And don't recall one freezing.
A line to house or in an unheated house? or exposed somewhere above ground? Sure.
And clearing the snow off and driving on an area enough can gain more frost depth.

Still , a 48 inch foundation rule remains in order to prevent frost heave.
Now lets add frost heave and spring temp changes to your frozen hole bottom theory.
Now you're cracking the unshored walls.
One thing mentioned in the prior well digging is the impact (literally) of falling objects when in a deep hole. Now we have crumling walls above us?
Or do you know something unique that prevents suck? Besides alleged smoke stains.

 

[Carl-NC]

It's basic thermodynamics. At depth, the soil and the groundwater hold a lot of heat. To make it freeze, you have to remove all that heat. But air has far less heat capacity and so to remove enough heat to make the hole freeze you would need to constantly pump fresh cold air down into the hole. You could probably freeze the hole to a depth of a few meters, beyond that not very likely.