Backfilling has traditionally been used in the Polish and German coal sites. However I have recently seen this becoming an important part of the Chinese coal industry. Some of the literature you may be interested in. They also discuss different backfill methods used at several mines.
Applied mineralogy, sometimes called process mineralogy, involves the identification and the mode of occurrence of minerals as they relate to the beneficiation of ores. Mineralogical data from general geological studies and hand specimen identification are inadequate. In order to select the best process scheme for a new ore, or to trouble-shoot effectively in an operating plant, an accurate identification of the minerals and their mode of occurrence are necessary. Mineral identification is accomplished using optical, physical, chemical and instrumental methods. Microscopical examination of thin sections and/or polished grain mounts is usually the first step.
Some examples of why detailed mineral information is important to ore beneficiation are:
Occurrence of the desired element in more than one mineral, particularly if the minerals have different responses to concentration. Examples: gold as native gold and gold in solid solution in pyrite; copper in chrysocolla and chalcopyrite; copper in chalcopyrite, malachite and Cu-bearing goethite; tin in cassiterite.
Variability in mineral composition (substitution, isomorphism). Examples: variability of Ag in solution in gold grains, high-Fe versus low-Fe content in sphalerite.
The presence of gangue minerals that can have an adverse effect on beneficiation; eg. montmorillonite and talc.
The presence of rare or unexpected minerals.
Even today, in the actual practice of mineral beneficiation, the role of applied mineralogy is often not fully appreciated and utilized. However, in order to optimize the treatment of any particular ore, applied mineralogy must play a prime role.
The mining industry has traditonally followed the model of linear economy, however lately the concept of circular economy (and related sustainability concepts) has been gaining traction. Waste is a critical issue along the whole metals value chain, from mining waste to eventually end of life products such as scrap steel from construction and demolition waste or the growing problem of electronic waste.
There are several examples of recycling secondary waste (batteries etc) for metal recovery, tailings reprocessing, using mine waste for backfills, usage of biproducts for alternate applocations that help minimise waste. However what is needed is an integrated approach to mining and metals waste. The mining industry as a whole needs to look beyond short term economic benfits.
The Sustainable Minerals Institute at the University of Queenslnd in Australia was doing some work around a framework that allows a mine site's performance to be assessed with respect to circular flow of minerals. Some details are provided in the article below.
Another point to be considered is that sustainability fo a resource relies on metallurgy, technology and understanding of mineralogy. The recovery rate of each metal depends on combination of those three factors.
For small ore bodies, ramp haulage is the default selection because it normally provides the most flexible and economical choice. A ramp (or adit) drive can typically be oriented to provide an underground diamond-drilling base and provide shorter crosscuts to the ore zone. The crosscuts are provided rapidly and economically because they provide a second heading for the main drive. It is possible to sink and develop from a shaft at the same time; however, this is a difficult and expensive procedure.
Another advantage to the ramp or adit entry is direct access by mobile equipment when trackless mining is to be employed. For a typical shaft, the equipment must be dismantled and reassembled underground. The set-up time required to initiate ramp driving is usually shorter than for a shaft. One to three months may be required to provide access and collar a ramp portal, while the collar, hoist, and headframe required for a shaft may take six months of site work. For medium sized ore bodies, ramp haulage may still be the best choice where the orebody is relatively flat lying. In this case, the ramp may have to be enlarged to accommodate larger trucks. In some cases, it may be practical to provide twin ramp entries to handle two-way traffic.
Belt Conveyor
For large, flat-lying ore bodies, a belt conveyor is typically the most economical method of hoisting ore. The legs of the conveyor are put into a ramp that has been driven straight (i.e. a “decline”) for each leg of the proposed conveyor way. If the soil overburden is very deep, or deep and water bearing, a ramp or decline may not be a practical method due to the extraordinary cost of excavating and constructing a portal. If the ground (bedrock) beneath the overburden is not competent or is heavily water bearing, a ramp or decline access may be impractical due to the driving time and cost.
Shaft System
For large steeply dipping ore bodies, a shaft system is usually best. In this scenario, it may be advisable to have a ramp entry as well to accelerate the pre-production schedule and later to provide service access to the mine.
Conventional Methods of Ore Transport
At the conceptual stage, it is normally better to consider only conventional methods for the transport of ore and resort to the unusual methods only under unusual circumstances. A good example of “unusual” is the aerial tramway installed across a fjord at the Black Angel Mine in Greenland to access an orebody located high on a cliff face.
Backfilling has traditionally been used in the Polish and German coal sites. However I have recently seen this becoming an important part of the Chinese coal industry. Some of the literature you may be interested in. They also discuss different backfill methods used at several mines.
https://link.springer.com/article/10.1007/s40789-014-0018-1
https://www.researchgate.net/publication/330472134_Properties_and_Application_of_Backfill_Materials_in_Coal_Mines_in_China