Is there any mining land register (a map showing all mining concessions) of the country?
No, there isn’t. Argentina doesn’t have a unifying concession system yet. Licenses for mining exploration or production are handled in each province. However, the National Secretariat of Mining has an online system where you can obtain information having certain data as name of the property or its coordinates. For updated, in-depth land registers, you should go to mining secretariats or departments of mining in each province. In general, most mining companies ask for these compilations to specialized consultants.