Reconstruction of the plan of mining concessions of the Sierra de Cartagena-La Unión (Murcia)

Abstract

During the 19th and 20th centuries, the Sierra de Cartagena-La Unión (Murcia) was one of the main metal ore producing districts in Europe. For the studies and projects carried out on it, it is often necessary to know the location of the mining concessions granted in a specific area and at a specific time. This article proposes a working methodology that allows the reconstruction of the general plan of concessions in a precise and orderly manner. The necessary documentation includes the demarcation plans that are part of the file of each mining concession and that collect their topographic and cartographic information. A database is created to allow its management and analysis. For the elaboration of the general plan, general working criteria are established, the concessions are represented and located by CAD and the possible presence of errors and misalignments is studied. These errors and mismatches arise both from data collection and from the preparation of the demarcation plans. They must be identified and quantified so that they can be reduced or eliminated. It is concluded that it is the magnitude of these errors that defines the scale to be used to obtain an accurate general plan. There is a very important antecedent of this work and it is the "Plan of the mines and transport routes of the term of Cartagena and La Union" made by Carlos Lanzarote at the beginning of the 20th century that, likewise, must be analyzed to determine the degree of cartographic precision that it provides.