Rats do a good job detecting land mines. It's better for a rat to die than a person to die. Scientists can always make more rats in a lab. We value human light enough that it's important to protect it, even if that means sacrificing a few rats to the cause.
Indeed, rats are the best animal to detect landmines. This animal is a harmful animal and is not implicated in any renewable ecosystem. So, if we put rats to work in order to save people, i would agree for doing so. We have to gather rats and puts them to work!
Using rats to detect landmines is a reasonable way to save human lives. Just as rats are used in laboratory research and other medical trials, we need to consider the benefit that animals offer by putting them to work. The value of human life outweighs the life of low level creatures such as rats.
Yes, animals should be used to detect dangerous landmines. We could train them to be able to identify land mines. Rats are much better at detecting TNT compared to people or dogs. Their exceptional olfaction can detect TNT for our purposes, and warn themselves against danger. Most of the time, they will not make any mistake so the use is ethical.