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The hydraulic fracturing (HF) technique is mainly used to precondition the orebody before mining in the block caving extraction method. Weakening the rock mass to enhance its caveability, reduce seismic risks and reduce fragment sizes are the primary objectives of HF in mining. HF is used mainly in large-scale deep underground mines with low-grade metal orebodies. In this paper, hydraulic fracturing simulation is conducted based on the finite element method to study the effect of simultaneous and sequential multiple hydraulic fracturing schemes. The input and in situ data used for this simulation come from the El Teniente porphyry Cu-Mo mine. The fracture propagation is modelled with the cohesive elements using a tractionseparation law. Comparing 3D and axisymmetric analysis, the similarity between fracture propagation shape and crack length prompted us to adopt axisymmetric analyses with reduced computational cost. Scenarios of simultaneous and sequential operations were analysed to consider the stress shadow effect, an understandable consequence of deformation during hydraulic fracturing. This comparison determined the fracture aperture, pore pressure, stress, and crack length. Due to the stress shadowing effect, different fracture lengths are observed. In addition, sequential injections have a subtler effect than simultaneous injections.

Se revisa los casos de eclampsia atendidos en 30 años en el Hospital Nacional Edgardo Rebagliati Martins, con una incidencia de 0,0.8% que no ha variado en los últimos 25 años. Ni la historia clínica anterior ni las características obstétricas y de presión arterial hicieron sospechar que se desencadenaría un cuadro de eclampsia en la mayor parte de casos, por lo que se sugiere un alto índice de sospecha en mujeres con aceleración de su hipertensión , dolor epigástrico, transtornos visuales, cefalea y ansiedad, así como terminar la gestación en breve lapso, una vez iniciado el tratamiento de las convulciones. La mortalidad materna fue 18,94% y la mortalidad perinatal 17,7%, tasas altas que nos deben hacer reflexionar sobre actitudes futuras que tiendan a mejorar éstos índices.