Opencastmining by an American company began in 1956, and continued after it was nationalised in 1973.
美国一家公司于1956年进行露天开采，一直到1973年秘鲁将其国有化。
2
Based on geological model of deposits and by means of CAD method, the authors put forward the building method of layered opencastmining geological model, whose layers are composed of bench.
本文提出了在矿床地质模型的基础上，应用CAD技术。建立以台阶为单元的分层式矿床开采地质模型的方法。
3
With the finite element method of material description, the rock mass in underground and opencast united mining engineering was simulated and analyzed.