Mining hydraulic roof support "Shields" used as a ranch gate entrance

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I noticed this ranch entrance gate as we were approaching the Hotchkiss National Fish Hatchery in Western Colorado. My guess is these gates are made from some kind of hydraulic roof bracing device used in the nearby coal mines. Maybe somebody out there has a better explanation? On February 24, 2016 yauwohn provided the following: "They are called shields, their job is to 'control' the roof convergence, NOT to 'jack the roof up' They form a safe working canopy and act like a fulcrum to 'throw' the weight back off of the face. Mining is a science, I was taught this at Tech during my apprenticeship with the UK NCB now long gone. Modern face roof supports are preset to 'yield' at certain pressures to control roof movement, biggest supports now days can yield at nearly 1500 tons. That puts positive pressure between floor and roof. A far cry from the first self advancing roof supports I was brought up with in the 1960's which were set to yield at around 50 tons." In September, 2011 "blaster19541 answered my question with this: "The jacks can hold hundreds of tons Go to youtube---long wall Miner ---and you can find more on the way they are used. JOY is one of the underground mining co. that have videos of them and how they work. Each jack works by its self . So if one fails the jack next to it will carry the weight. That is the beauty of the Long wall system. The men always work under the shield/jack." Thanks for the info! Here's my personal webpage about Colorado: 05-11-2011

Published by: zeekzilch
Published at: ۹ years ago
Category: علمی و تکنولوژی