I’ve recently been studying mine operations for a layout I’m working on. I came across a great site, Appalachian Railroad modeling. They make several references to shipping ammonium nitrate deliveries to mines in covered hoppers along with coal hoppers. I was wondering what timeframe this would have been in, I model the 50s. The site seem to focus on the late 60s, 70s, 80s. I am not sure how this product would have been processed/handled and I assume it was used for blasting, etc.
While the use of ANFO (ammonium nitrate + fuel oil) explosives had been studied since 1921, the first use in commercial mining wasn’t until 1956.
Due to the liquid nature of site-mixed ANFO, it isn’t very practical for use in horizontal boreholes. Therefore, it would primarily be used in open-pit mines, where the usual procedure is to drill vertically downward rather than horizontally into a vertical face.
If the ammonium nitrate is delivered in covered hoppers, then the mine would require delivery of fuel oil in tank cars in order to have the necessary ingredients for site-mixed ANFO.
FWIW, the Walthers New River Mine was actually the processing plant/loadout for an open pit mine located on the opposite side of an intervening ridge. Since there was no direct road route from the loadout to the pit (the road connection was circuitous, including county roads) explosives and their components would not have been delivered to the modeled structure. Contemporary photos show only a small office/locker room structure at the loadout.
Chuck (modeling Central Japan in September, 1964 - with underground coal mines)
Prilled ammonium nitrate is unloaded by gravity from a covered hopper, and usually augured into either a steel storage silo for later gravity discharge into a truck, or augured directly into a truck – the covered hopper itself is the storage bin. There’s no special precautions taken with the ammonium nitrate; it’s just plain old fertilizer until mixed with diesel fuel. Some locations build a very small concrete pit. Others just slide or roll the portable augur under the car. There are more than 1,000 team track locations in the U.S. where ammonium nitrate and other similar materials are unloaded into trucks using portable augurs at this time.
Every open pit mine I have ever been to in my railway career received its diesel fuel by truck from a refinery. I’ve never seen a tankcar of diesel fuel delivered to a mine. I wonder where it does occur. We looked at a move a while ago from a refinery to a plant that was by rail about 200 miles. The requirement was about 3 27,000 gallon tankcars a week, which is an enormous amount of diesel fuel for a mine. Trucking was cheaper after we factored in the car lease cost because the turnarounds on the cars would be too poor. We’d be lucky to have gotten 12 trips a year out of the equipment.