This article discusses appropriates techniques for deconstruction. These are useful for construction projects (ie blasting of rock layers), ...
Gunpowder
Regular black powder is simple to make with common materials and environmentally friendly. It is useful as an initiator (a compound which ignites the main explosive) and is also used as a slow or quick match (= a fuse).
Slow or quick match
As explained above, this is a fuse. A fuse is a piece of string impregnated with a highly burnable material intented to ignite the initiator. The highly burnable material we'll use is black powder. Fuses are more environmentally friendly than electrical ignitors, since the burn up fully.
AN/FO
This compound, known as ammonium nitrate/fuel oil in full, is a substance that is already in wide use in coal mining, quarrying, metal mining, and civil construction (undemanding applications). Though made with components of the petrochemical industry (fuel oil or alternatively motor oil and gasoline), it still fits the requirements of an appropriate explosive. This since it's cheap, easily available (via commercial establishments) and relatively environmental (since the compound is ignited anyway, leaving no trace in nature). The ignition of the compound will be almost perfect, since it is intented to happen underground, in a confined space. As discussed above, we'll use gunpowder as the ignitor, which although uncommon is much more easy to make than HMTD, ...[1] and more environmentally friendly.[2][3][4]