Design of pillars size in under ground mines by ground reaction curve method

Subject Areas :

Kamran Goshtasbi ¹ , Shobeir Arshadnejad ²

1 - دانشگاه تربیت مدرس تهران
2 - دانشجوی دکترای استخراج معدن دانشگاه آزاد اسلامی واحد علوم و تحقیقات

Received: 2016-09-05 Accepted : 2016-09-05 Published : 2007-09-23

Keywords: Pillar, Underground mine, Ground reaction curve, Numerical modeling,

Abstract :

Mining methods are mainly depending on physical and geometrical structure of ore bodies. Room &pillar mining is very important in underground mining methods. Because of it is simplicity, highproduction and low cost of operations. Room & pillar method includes some intersecting tunnels in orebody, for stability of these tunnels, some parts of ore body must remain in the form of columns or socalled pillar. Designing of the pillars is very important for increasing of the performance anddecreasing of ore loss. Hence many empirical formulae are presented for designing of the pillars, butbased on limited data. In fact, the particular restriction of each formula limits its application in variousconditions and ore bodies. In this paper a new method is suggested for determination of optimumpillars design in various conditions by numerical modeling and ground reaction curve. By this methodall of rock mass geomechanical and geometrical characteristics can be considered for designing of thepillars. This new method is based on ground reaction curve by making 18 models in 30, 40 and 50meters depth with different width to height ratio (W/h) of the pillar. Each of the resulted curves inlinear part which states the elastic behavior of rock mass determines the desirable width to height ratio(W/h). An Underground salt rock mine (Soltan abad’s mine) was selected for validating of thesuggested method. The W/h for stable pillars in the mine is between 1.3 and 1.6. The result obtained ofground reaction curves is 1.375 for W/h which showing the accuracy of suggested method.