Howdy my good friend Marius,
If thats the way you see it, I have no problem with your reasoning. I however I believe that the word "Escardadia" is Peralta for tailings.
There are many words that don't make it to the dictionaries because they don't get used enough, however many understand them. Some posters tend to make up words every now and then, and we know what they mean, even if they are not in a dictionary.
The word "Escarda" means to weed, or separate, such as to separate the wheat from the chaff. "Anda y escarda el trigo" go separate the wheat from the chaff. "Voy a escardar" I am going to weed, or separate. "Estoy escardando" I am weeding or separating. So in my honest opinion, "Escardadia" would mean what remains after the weeding, or separating, such as weed cuttings, chaff, or tailings.
Since the map does not lead to a garden, but to a mine, and the "Escardadia" is shown below the "hoyo", pit or hole, I would say it is safe to say that is means tailings.
Homar
Homar