The access to Urucum mine is at the base of the Morraria de Urucum, composed of sedimentary rocks, a very steep rockface. Several rockfalls events in the past required that the company take action to mitigate risks, leading to a diagnostic and protective measures. Initially, the analyzes were based only on a point cloud, due access restrictions related to the pandemic period, resulting in a preliminary design of rockfall barriers and drainage. With the conceptual design, an extensive field mapping was performed, and the project revised, culminating in a drastic reduction of necessary interventions. The optimization it was possible through identification of differential weathering in the jaspilite strata, which allowed a new geomechanical model, better probabilistic analysis of block size distribution and thousands of rockfall simulations. This case is an interesting example of how the use of modern tools helps in projects, but it shows that they should be used with caution.
The area of this study consists of a manganese underground mining plant, the Urucum Mine, located in the city of Corumbá, Midwest region of Brazil, close to the border with Bolivia. The mean coordinates of the area are in UTM 435.255 E and 7.878.7684 S (WGS84), and the map with its location is presented on Figure 1 (a), a Google Earth image.=.
Upslope of the main entrance of the underground mine the Morraria Urucum is present, a natural slope with more than 300 meters high that can be divided in 3 homogenous regions, see Figure 1 (b): a) Crest Region where the slope is about 50° of inclination, there is top soil, some isolated rock faces b) Rockface Region where a fractured and vertical rock slope is present (jaspilite) and c) Base Region a part of the slope where the inclination is about 20∼30° and one can find dense forest vegetation and top soil, a talus type formation. In addition, on Figure 1 (c) the vertical rockface can be observed on frontal view.
