Sand Pile Bedding Down for Winter
I built our driveway so that the milk truck can get high enough up the mountain on our farm that the whey all gravity feeds down from the tanks to the troughs for the pigs. In the winter this necessitates sanding the driveway for the milk truck since its tires are not to be allowed to have studs on them due to its weight class. The previous milk trucks were four wheel drive but the new one is only two wheel drive making this even more critical.
We buy about two full dump truck loads a year of ‘dry’ sand for this purpose. That’s roughly 24 cubic-yards. This year I bought three truck loads in an effort to give the sand pile more mass in the hopes of keeping it from freezing. If it freezes up hard then I have to use the backhoe to break it up and that is slow going.
You might wonder why we don’t just use dirt from our own farm’s sand pit. The problem is our dirt has too much clay in it – at least of the spots I’ve dug so far. Basically we want pure sand and a sharp sand at that to give the milk truck good traction. Last year we got a powdery sand from a new pit and that was far less than ideal.
I don’t use salt in the sand pile because the chloride corrodes metal, damages concrete, harms plant and aquatic life and can kill the pigs. Salt is cheap but not the solution. This year I am trying something called Calcium Magnesium Acetate (CMA) which costs a lot more than salt (13x) but is supposed to do the job of preventing freezing without any of the downsides of salt. We’ll see how it does. I mixed 55 lbs of the CMA into one end of the sand pile as a test.
The hay bales that ring the sand pile are another little trick to help prevent freezing. Hay is a great insulator. As I move bales out to the animals all winter long from the other hay depots I expose unfrozen patches of dirt† beneath them. This demonstrates how wonderfully the hay has insulated the soil. Between the bales where the hay is not covered the ground is hard but under the bales it is soft and diggable. The pigs love rooting there during the winter.
With the hay surrounding the sides of the pile and the warm earth below sending up heat we’re doing pretty well. Then the trick is to insulate the pile on top so we retain the warmth. That’s what Ben is doing in the photo above. I set an open bale of hay up on the pile and he worked at spreading it out evenly over the top of the sand. Each time we open the end of the pile to sand the driveway I do get a little hay in my scoops but it doesn’t seem to be a problem.
Lastly is the top cover, two tarps that are helping to make it so that precipitation is shed off the pile rather than soaking in and freezing up. This is very important but not enough – thus the insulation. I would love to have a permanent roofed over sand pile but that’s a future project – it’s been on my list for a while.
An idea I have is to put solar panels on said south slanted sand shed roof or the bank below the pile that is south facing and circulate hot water below the pile. This would then warm the pile even more, further helping to prevent freezing in the coldest depths of winter. It can get -45°F for extended periods. The solar heating system could either run off of a thermo-siphon or a very small pump powered by a solar electric panel. I’m inclined to the simpler system of the thermo-siphon but that has siting issues.
I’ve also toyed with the slightly nutty idea of putting a small rocket stove consisting of a long heavy metal tube with a chimney at one end in the middle of the pile that I could burn wood in if necessary when the winter weather drops down into the deep negative temperature zone. That would also serve to drive moisture out of the pile. We have plenty of scrap firewood so that is not an issue. Kiln dried sand from the inside out.
Outdoors: 26°F/18°F Sunny
Tiny Cottage: 69°F/67°F
Daily Spark: The good things in life are like ogres – they have layers.
†I routinely scoop up a little of that dirt to give to the pigs as it is filled with minerals they need such as selenium. Pigs without selenium develop white muscle disease. We had this happen and discovered that those pigs who had access to our dirt were protected and those who started getting the white muscle disease recovered when they got pails of dirt. In the summers the pigs are fine since they have access to our good dirt. The problem is that most of the hay we buy comes from a farm that is selenium deficient. Giving the pigs some of our dirt during the winter solves the issue.