Job trials Sandvik Superior jaw plates
First publishedin Aggregates Business Europe
Scottish Highlands-based company G.F. Job says its Sandvik designed and manufactured Superior tooth jaw plates have doubled the lifetime of its jaw plates. The company, based in Nairn, Inverness, offers a range of services, including earthmoving, civil engineering, heavy haulage, recycling and contract crushing.
It owns five quarries, crushing mostly hard, abrasive granite and glacial cobbles, and it supplies aggregates to leading suppliers in the Scottish Highlands. It also owns a range of Sandvik mobile crushing and screening equipment, including four tracked jaw crushers, and one, a Sandvik QJ341, is used in the same granite quarry for most of the year, producing 500,000tonnes of material to feed an aggregate processing plant.
G. F. Job has used a variety of jaws to test durability and performance, and a history of tonnages produced from each jaw has been recorded to give a true account of performance in relation to costs. For this reason, it decided to trial the new Superior tooth jaw plates on this machine.
Sandvik says that it has developed the new profile of jaw plate, designed to increase durability and productivity, and decrease operating costs and service time. The Superior plates are designed around adding material where it matters, and the new profile allows for a higher percentage of the jaw to be worn, which results in longer wear life and less manganese waste. The improved tooth profile also allows for better breakage and improved material flow, producing a more cubical product and a higher quality product shape, while the special design makes the plates easier to turn over or replace.
Initial test data from the G.F. Job trial is said to show average output increased from 200 to 250tonnes/hour and wear rates increased upwards of 30%. “In this particular granite application, previous jaw plates have been ranging between 20,000-30,000tonnes of crushed material and that is the life of the jaws,” says Graeme Watt, plant manager for G.F. Job.
“Since we went onto this new jaw we’re up 50,000-55,000tonnes for the life of the jaw. If you go into a limestone quarry, you will get double but this is a hard abrasive material. The new jaw plates are reducing the load on the crusher, and therefore you are creating better fuel economy whilst also reducing the physical hardship on that machine.”