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BAODING JINGBO RUBBER BELTS CO.,LTD
Summary of Safety Accidents Caused by Conveyor Belt Fracture
In coal production, belt conveyor is an important transportation equipment. Some of the main conveyors are responsible for one or more mining areas. However, due to the long-term, high-load operation of conveyor belt and some unexpected factors, such as the direct impact of gangue on the belt or metal blocking tape, the belt will suddenly break; for the strong belt of the steel wire rope core, the transverse breakage of the belt will occur because of the corrosion, fracture of the steel wire rope core or the pulling of the steel wire rope core of the vulcanized joint of the belt. Moreover, most of the fault zones occur near the driving drum and on the bearing zones with large slope changes. Once the belt breaking and sliding or the reversal accident caused by the failure of backstop occurs, the conveyor with large inclination angle, long distance and heavy load will destroy the frame of the belt conveyor, damage the equipment and block the transportation roadway, resulting in a long period of shutdown and major economic losses, even casualties and serious consequences; moreover, the belt breaking accident is very common. In order to ensure the safe production of coal mine, the transverse protection of belt breakage of upper conveyor must be paid more attention. It should be actively prevented to avoid the occurrence of belt breakage accidents, and take certain protective measures. When the belt breakage occurs, the protective device can brake the sliding belt timely and reliably, so as to avoid malignant accidents.
Belt breaking accidents of belt conveyor transverse belt breaking accidents often occur. Below are some of the published belt breaking accidents and statistical data in the paper. (1) On May 20 and July 31, 1994, in 330 mining area of Qiwu Coal Mine, Shandong Province, two consecutive belt-breaking accidents occurred in the normal operation of the belt conveyor. Although no casualties were caused, the direct economic losses were about 98,000 yuan each time, and the indirect losses were more than 2.5 million yuan. In the first accident, the vulcanized joint numbered 88-12-8 fell off and broke when it ran to a large slope change point about 150 m below the head of the belt conveyor. Under the action of load and gravity component, the broken tape accelerates gradually and slides rapidly until it can no longer slide, and the sliding distance is more than 500 m. More than 150 rubber belt idler supports were damaged by impact, more than 60 idlers were damaged, and more than 20 suspensions of overhead passenger devices were destroyed. In the second accident, the vulcanized joint numbered 94-5-2 broke off at about 200 m below the head of the belt machine, and the tape sliding distance was more than 550 M. The situation was basically the same as that of the first accident.
2 Zhuxianzhuang Coal Mine of Huaibei Mining Group Company, with the gradual improvement of mechanization degree, the output of raw coal has increased year by year. At present, it has exceeded 1.7 million t/d, and more than 85% of raw coal needs strong conveyor to transport. Since 1996, five ST-type wire rope core conveyors have been installed and put into use in Zhuxianzhuang Coal Mine. The Total belt length of the conveyor is 13 200 m. With the increase of service life of conveyor belt, aging phenomenon appears to varying degrees, which results in the decrease of bonding strength between conveyor belt cover and belt core. At the end of 2002, there were five accidents of belt joint breaking of conveyor, which directly affected the safe production of the whole mine.
Three Datong Coal Mine Group Co., Ltd. has 12 belt conveyors for main hoisting inclined shaft and 11 belt conveyors for main conveyor for underground inclined shaft. The slope of inclined shaft is 14 to 16 degrees, the rubber bandwidth is 1 to 1.4 m, and the length of the machine is 400 to 1 100 m. From 1989 to 1995, seven belt breaking accidents occurred on belt conveyors in main inclined wells, affecting production for nearly 400 hours and affecting production of 300,000 tons. The belt breakage accident not only affects the production and economic benefits, but also seriously damages the underground equipment, and even threatens the safety of workers.
4 Pingdingshan Mining Bureau till 1996, there were 17 steel cord belt conveyors in operation, including SQD-440 upward conveyor with large inclination, STJ/4X2805 steel cord belt conveyor with 1 000 t/h and so on. A total of 10 mines use steel cord belt conveyors, of which 8 mines have experienced belt breakage accidents. 58.82% of the total belt conveyors suffered from belt breakage accidents. According to incomplete statistics, as of August 1995, there were 16 accidents of steel cord belt breakage, which affected the production time 1 706.2 hours and the output more than 200,000 tons. Fifteen of them occurred at the joint, accounting for 93.75% of the total.
Jingbo Rubber reminds you that conveyor belts should be regularly maintained and replaced to avoid unnecessary safety accidents.