A dragline this size has no wheels at all.<\/p>\n
It rests on a round steel tub, and it moves by lifting part of its own weight onto two shoes, shifting, and setting itself back down.<\/p>\n
One cycle covers a few feet. Then it does the whole thing again.<\/p>\n
Which is fine when the next cut is next door<\/strong>.<\/p>\n It is not fine when the coal sits on the far side of the lease with a working rail line in between.<\/p>\n So somebody put the machine on tires<\/strong>.<\/p>\n Walking is not driving. Nothing on a dragline turns against the ground.<\/p>\n The machine lifts, leans, sets down and repeats, and every stage of that sequence is a full load transfer through hydraulics and steel.<\/p>\n So the speed limit is not power. It is cycle time<\/strong>.<\/p>\n Add up enough cycles and the machine covers roughly six tenths of a mile in twelve hours, working without a break.<\/p>\n A wheel inverts that. The load transfers once, at the start, and after that the weight simply rides.<\/p>\n Everything the engine does goes into forward motion rather than into picking itself up<\/strong>.<\/p>\n That is the whole trade, and it moves the hard question off the machine and onto the ground underneath it.<\/p>\n This one is an older American built dragline with a boom 325 feet long, the kind that throws a bucket out over a pit and drags it back full of overburden.<\/p>\n Working weight runs about 6.8 million pounds, near enough 3,400 tons<\/strong>.<\/p>\n It sits on a coal lease in central Queensland, in the Bowen Basin, where pits run for miles and the dirt on top has to come off before anything below is worth touching.<\/p>\n The coal it was needed for lay in the southern pits.<\/p>\n Between the machine and that coal ran an export rail corridor carrying loaded trains from several mines out to the coast.<\/p>\n Nobody was going to close that<\/strong> for a month.<\/p>\n Hydraulic jacking towers went in underneath and raised the entire machine about 8.2 feet clear of the floor.<\/p>\n Older practice in Australia used climbing jacks, lifted in stages on stacks of timber packed by hand. The towers used here take steel cassettes at the base instead, so a crew feeds the lift rather than building it<\/strong>.<\/p>\n The load then came down onto five groups of transporter modules, 28 axle lines apiece, riding on 560 tires.<\/p>\n Spread that thin, ground pressure stayed under roughly 1,840 pounds<\/strong> per square foot, and steel mats went down wherever the floor was soft.<\/p>\n The run covered 16.7 miles in ten days, averaging close to five miles a day on transporters rated to three miles an hour.<\/p>\n The rail crossing was the fixed point. A temporary ramp had to be built, used and removed inside a 72 hour shutdown taken in August of 2025.<\/p>\n The branch manager on the job gave the reason without decoration: competing work in the area meant the next available window would not have come around for another three months.<\/p>\n The claim here is about pace, not size.<\/p>\n A fully assembled dragline had already been rolled across Queensland once before, in 2013, and that trip ran close to 62 miles between two mines, more than three times this distance.<\/p>\n What is new is ten days and five miles a day, at this weight, with a live rail corridor sitting in the middle of the route.<\/p>\n There is also no referee. Heavy transport records get announced by the contractors that set them, and nobody independent audits the distance or the clock<\/strong>.<\/p>\n The method has hard edges too. It wants a floor that will take the pressure, a route that can be graded, and a structure willing to be picked up whole<\/strong>, which rules out plenty of machines, including the one cut into 27 separate loads and hauled by road<\/a> across Texas, or the single lifts that go to the largest crawler cranes<\/a>.<\/p>\n A dragline that is not digging is not a slow asset. It is a stopped one.<\/p>\n These machines strip the overburden that every truck and shovel behind them depends on, so a month of walking is a month the pit does not advance.<\/p>\n That is the arithmetic that pays for 560 tires and a fleet of jacks.<\/p>\n What has changed is where the binding constraint sits. It is no longer the gait of the machine, as the contractor’s account<\/a> of the move sets out.<\/p>\n It is ground conditions and a rail timetable, and both of those are somebody’s schedule rather than a law of physics, as trade coverage<\/a> of the job recorded.<\/p>\n Schedules can be argued with.<\/p>\n The jacking towers<\/strong> turned out to be the cheap part<\/strong>.<\/p>\n","protected":false},"excerpt":{"rendered":" A dragline this size has no wheels at all. It rests on a round steel tub, and it moves by lifting part of its own weight onto two shoes, shifting, and setting itself back down. One cycle covers a few feet. Then it does the whole thing again. Which is fine when the next cut … Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":2336,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[],"class_list":["post-2238","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-heavy-machinery"],"_links":{"self":[{"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/posts\/2238","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/comments?post=2238"}],"version-history":[{"count":3,"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/posts\/2238\/revisions"}],"predecessor-version":[{"id":2337,"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/posts\/2238\/revisions\/2337"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/media\/2336"}],"wp:attachment":[{"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/media?parent=2238"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/categories?post=2238"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ecoportal.net\/uk\/wp-json\/wp\/v2\/tags?post=2238"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Stepping moves weight, rolling only carries it<\/h2>\n
The machine and the hole it works in<\/h2>\n
Eight towers, 560 tires and a fixed shutdown<\/h2>\n
What the record covers and what it leaves out<\/h2>\n
The limit moved off the machine<\/h2>\n