This paper studies the issue of tax evasion in the context of the underground economy. A dynamic general equilibrium model is built where individual households and entrepreneurs decide rationally whether to go underground and under-report their earnings. These behaviors affect tax revenues, which are used to finance productive public services. This model is applied to the Czech Republic, becaus...

A gully is an excavation cut in the immediate footwall or hangingwall of the reef for the purpose of enabling the removal of rock from the face or providing access to the face for mining personnel or material1. The gully sidewalls and hangingwall often pose a serious stability problem in the gold and platinum mines in South Africa, since records of fatal rock-related injuries show that they are...

underground economy affects important indexes such as formal gdp, unemployment, consumption, production and etc. therefore it is necessary to identify elements and factors which affect underground economy to restrict it. surveys and studies indicate the size of iran’s underground economy is high and taxes, quantity and quality of regulations and performance of formal economy are the important f...

The foundation framework for underground spatial data aims to establish the platform for the underground spatial data sharing and integrating. The reasons lie in that: a) the long-term development of city construction has accumulated abundant underground spatial data and information; b) the development and utilization of city underground space demands for clear, detailed and visualized comprehe...

In view of the severe ground pressure behavior and spontaneous combustion risk goaf in fully mechanized top coal caving face with deep buried weak cohesive roof thick seam prone to combustion, combined theoretical analysis mining overburden structure field engineering practice, structural characteristics rock strata law are studied. The results show that: stope also has phenomenon surface step ...

Wireless Underground Sensor Networks (WUSN) constitute one of the promising application areas of the recently developed wireless sensor networking techniques. The main difference between WUSN and the terrestrial wireless sensor networks is the communication medium. The propagation characteristics of electromagnetic (EM) waves in soil and the significant differences between propagation in air pr...

Due to the high attenuation of radio frequency (RF) signals in underground mines and the statutory power restriction of communication gadgets especially for coal mines, the wireless communication systems have restricted applications in the underground mines. The paper discusses different radio frequency communication techniques being employed for Indian underground mines. Experiments were condu...

The history of backfilling underground mined-out voids dates back to the beginning mining several centuries ago using rockfill. Currently, there are three major types backfill: rock, hydraulic, and paste fill. When backfill is required be exposed from beside or underneath, cement binder added. Cemented hydraulic fill most commonly used as it has existed for over 80 years. In early 1960s, a seri...

Due to its unique sensitivity to hydrogen protons, magnetic resonance sounding (MRS) is the only geophysical method that directly detects water and can provide nondestructive information on subsurface aquifer properties. The relationship between the surface MRS signal and the location and characteristics of aquifers using large-coil (typically 50-150 m) sensors has been discussed based on forwa...

Many coal mine companies have established underground safety monitor and control systems. However, the safety management information can only be displayed on the 2D maps or as reports. In this paper, a new method that combines the VR technologies with underground mine safety monitoring technologies was explored. A desktop virtual reality program for underground coal mine, called VRLane, was dev...