Breaking Rocks Manually - Plugs & Feathers
A piece broken off a granite rock using plugs and feathers
Plugs and feathers is an old stone mason technique for breaking rocks. A series of holes are drilled into the rock along a line which is to be broken. The plugs and feathers are inserted into the holes. By gently tapping them individually an increasing force is exerted on to the rock, which finally breaks the rock along the drilled line.
This is a somewhat forgotten technique, which can be used to break rocks into smaller pieces. It is a fairly simple mechanical way to break rocks using a wedge to create a perpendicular force to break the rock. The bottleneck in this technique is drilling the holes in the rock to be split. This will require some sort of power tool if any sort of speed is to be achieved, but stone chisel techniques can also be employed as was done in the past. This is a more labour intensive technique versus blasting or larger mechanical pneumatic breaking tools. If the labour costs are suitably low and the labour can be organized efficiently, this technique can be cheaper than blasting or using heavy machinery. In any case it is a more gentle and precise way of breaking rocks. It can be used in areas where there are special environmental or social concerns as well as remote areas or tight spaces where heavy machinery cannot reach.
In developing countries, where labour is cheaper and more abundant than in developed countries this can be a more appropriate approach to civil works projects compared to employing heavy machinery and or blasting. It creates jobs and is beneficial to the local communities where the project is executed. The alternatives bring benefits to companies renting out the machinery and blasting contractors who reside in the cities, away from the rurual communities. The critical factor is to manage the worker effectively and having the right equipment to drill holes into the rocks.
The author used this technique to break and remove rocks from excavation works for two penstock pipes with a total length of 1900m as part of two hydro-electric projects in rural Malawi.
The tools can be purchased in different sizes from specialized mansonary suppliers, but with some metal working skills and the right tools they can also be manufactured from re-bar and spring steel.
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