"Hot Mix LDO" isn't a standard term within the domain of fuels or industrial products. It seems to be a combination of different terms used in an unconventional way "Hot Mix LDO" could be an unconventional or local term used in a specific context...
Black LDO (Light Diesel Oil) is a blend of residual oil and distillates feed. It's primarily used as industrial fuel and in stationary or slow speed diesel engines...