Simulation of Multi-muon Events from EAS at Shallow Depths Underground

The Monte Carlo program ARROW, based on GEANT and using GHEISHA at energies below 30 GeV, is developed for simulation of the hadron and muon components of extensive air showers with primary energy $10^{12}-10^{17}$ eV. Calculations of the characteristics of multi-muon events as observed underground by the LEP detectors are presented and their dependence on the primary cosmic ray composition and some basic assumptions of the hadronic interaction model is discussed.