Yielding Steel Prop

This product relates to a device for roof support of underground mine/tunnel. It particularly relates to a mine support device which additionally providing unique yielding mechanism, continuous monitoring of roof load of underground mine/tunnels/roadways with simple, easy and safe remote release mechanism.

In general, underground mine/tunnels / roadways are supported, especially in India, by using wooden cogs/props and roof bolts. Though in most of the mines roof bolting culture has started, but passive support systems cannot be avoided. In board & pillar mining and longwal mining operation these types of supports are used extensively in addition to the roof bolting.  But as wood is becoming scarce, there is need for suitable alternative supports to replace timbers in mines. Further, in deeper mines roof load decreases , thus to run the blasting gallery method of mining slow loading yielding props are required in addition to other support systems.  

Keeping in mind the requirement need by the industries and as per the Indian mining conditions the support should be of greater longevity, light enough for easy portability and requiring less maintenance. Further, it should have facilities for height variation, sufficient yielding, continues load monitoring and releasing remotely as the coal seam thickness varies widely in Indian mines. Then, it should have ease in operation by even an unskilled worker. Additionally, the device must be economically viable and acceptable to the miners. Many standing props have been designed in past like friction prop, hydraulic prop, screw prop, pit prop etc., but none has the all facilities as mentioned below in Figure 1 & 2.

After numerous attempts such innovative prop consisting of multiple disc springs has been designed and developed at CSIR-CIMFR of which the details description has been given above.

This device useful for support of underground mine tunnel / roadways in accordance with the specification. Laboratory trial was conducted at CIMFR Laboratory on the advice of Directorate General of Mines Safety (DGMS), a statutory body of Govt. of India / ECL. This prop was tested for axial load test, eccentric load test, and overload test. In addition to that fatigue load test was also conducted for 500 cycles and initial 50 cycles were observed and studied. After successful laboratory trial ,field trials were conducted thereafter   in Chinakuri Mine -1 Eastern Coalfields Limited (ECL), Sanctoria, Burdwan (West Bengal) in longwall panel and development district. The systematic field trial was widely accepted by the mining authority .

This product has been DGMS approved and the patent thereof has been granted in India & USA including PCT countries.

• It replaces timber completely thus maintaining ecological balance.
• No wedging is required.
• Setting load can be provided.
• Installation is very easy.
• Dismantling is quick.
• Height variation is possible.
• Provides yielding characteristic.
• Easy withdrawal possible, even from a remote distance.
• All the parts are detachable thus easily transportable.
• Longevity of the prop by changing element(s) of yielding spring only, if required.
• Very compact and robust.
• Minimum maintenance.
• Very cost effective, thus economically viable.
• Roof load coming as well as convergence of the roof can be continuously monitored with the help of the pointer attached with the disc spring. Thus no separate measuring instrument is required for this purpose.
• Variable yielding range
• Simple, easy and safe remote release mechanism.