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Modelling the flow of a non-homogeneous ore is an important element needed to identify ore parameters for the purpose of ore processing control. The simulation model of the underground ore haulage system with the implemented function of estimating ore qualitative and quantitative parameters was built in the dedicated FlexSim simulation environment to address this issue. The transported ore is averaged in transfer and retention points, for instance in ore bunkers. This fact renders the modelling of ore flow inside the bunker a necessary part of the simulation. The movement of the granulated material, restricted by the geometry of the floor and walls, is modelled using Discrete Elements Method (DEM) with regard to the technological cycles of bunker filling and emptying. An experimental task was conducted on the site to identify the transport time of RFID tags that flowed together with the portions of ore they annotated. Empirical model of the transport system in the KGHM Lubin mine was parameterized with mean retention times obtained in DEM simulations in order to be compared with the RFID-tag experiment. The as-parameterized FlexSim simulation for one-chute bunker discharge variant yields tag transport times comparable with the experimental data. The results proved the reliable description of the ore transport time in the FlexSim model. [ABSTRACT FROM AUTHOR]

Explains the development of the Polish Ministry of Labour in 1972. Organizational structure of the labor administration; Features of the Ministry's program; Overview of existing bilateral and multilateral cooperation arrangements in labor administration as of August 1974.

Cardiac tumours have been frequently reported in patients with tuberous sclerosis but their incidence at different ages has been evaluated in only a few studies. We performed echocardiography in 47 children with tuberous sclerosis and found tumours in 22 (47%). In none, except one newborn, did we observe any clinical symptoms of heart failure. Tumours were more frequent in children below 2 years of age (91%) than in older children. As other signs of tuberous sclerosis are often absent in infants, echocardiography may be regarded as the most useful diagnostic test at this age. Follow up studies were done in 12 children and tumour regression occurred in 6 patients. [ABSTRACT FROM AUTHOR]