pounders vs rotary
There are two types of machines used in creating wells, pounders and rotarys. Rotarys have nearly taken over the well drilling industry due to their speed and simplicity but many would argue that pounders are superior for the Granite State.
A rotary drills down into the bedrock and discharges the waste upward with high pressure air. A simple hole is created in the bedrock and some of the drilling discharge is actually packed into the pores in the rock by the pressure, limiting the groundwater flow. Rotarys work really fast and a well can thus be far less costly overall to produce.
A pounder will hammer a drill bit, rotating it just a little with each blow. The hammering action can be really tiresome to listen to and is much slower than a rotary, but each blow will actually fracture open cracks in the bedrock and this can drastically increase the flow. About every twenty minutes or so the operator will need to withdrawn the rotary hammer bit and lower a clamshell into the hole to withdraw the waste. This slows the operation down even more.
The end result of favoring a pounder is that it will shatter open the rock around a well again greatly increasing the water flow. Hydrofracing gives a quick burst of pressure into the drilled hole in hopes of producing the same shattering but much of the fracturing effect can be lost due to silt being forced even deeper into the grain by the burst of pressure.
My last two wells were done using a rotary to punch down to the bedrock, and then having Dave Kelso from Canterbury set up his pounder over the drilledwell to hammer the last 100 feet. My current well is 270 feet total with 170 feet of casing and has a little too much iron to be perfect, but the amount of water I have is endless. Dave also did a well for a buddy on the other side of New Hampton and there he was lucky enough to hit ledge in less than twenty feet, went only 100 feet total, and Bob too has an endless supply of water. Shallower wells generally have higher quality water and Bob's would rival the Castle's.
I think that Dave has retired and is getting ready to sell his pounder, but if you can find someone that still uses a pounder it is a great way to revitalize an old drilled well
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