Large 50 inch lumps can be handled. Tarbela dam, Syncrude Canada, LImestone in Japan are a few that come to mind. Loading is critical. Belt construction and idler support and trough need special design considerations. The speed will obviously be very slow.

The rocks other dimensions need to be considered. to quantify the maximum size. ■

For one thing you are going to need a huge belt-

84-96 inch wide due to the oversize copper ore, for the distance you are moving the ore 1400 feet

it might be simpler to just install a wide low profile feeder breaker to crush the copper ore down to minus six inch and and feed a 36 inch belt with 3 transfer points due to the weight of the ore.

Short of having low profile haul trucks such as the Wagner MT422 ore cars, Volvo haul trucks or Kiruna trucks as an example, I do not see another solution.

WR Stamler and Long Airdox make belt feeder breakers that will break copper. ■

Did something similar in early 80's at a coal plant in Alberta to handle 48" frozen lumps or petrified stumps from ROM to crusher.

From memory:

84" wide fabric belt, maximum # of plies and maximum cover thickness available from Goodyear

14" dia custom made rubber tire impact idlers on an isolated feed section

grizzly to put a layer of fines down under the lumps

20 degree idlers

slow speed, full skirts, probably 60-100 ft long

spare belt in stock

Or, better still, feed straight into the crusher from an apron or reciprocating feeder. ■

I agree that the solution is a slow wide belt, at least 2 metres wide but I would not be using a steel cord belt but a heavy duty fabric reinforced belt. The impact energy of such large rocks will be very hard to control and there is a high likelihood you will damage cables. Given the belt width etc tensions and stretch will not be a factor stopping you from using a fabric belt. By over designing the carcass to withstand impact you will get a better belt life. The design of the rock box type feeder is also important as you will not want the large rocks to bridge out or jam anywhere.

Col Benjamin ■

In actual fact, Kidd Creek Mines in Timmins, ON, Canada has a belt, I believe it is a 72" wide that has 5 foot lumps and it is Copper Ore as well. The system utilizes Precismeca Impact Garlands with 60mm dia. Shafts. I did the drawings back in 1986 and the system has been running effectively since 1989. ■

Hello Grosenth..

The material can be conveyed, but you have to be extremely carefull about the loading.

Once on the belt, and assuming you don't get any roll back, all will be well.

If you limit the impact energy of any lump onto the belt to less than 2000 Joules and use sprung mounted garland idlers combined with a suitably resilient belt, you can do it. This means however that the vertical impact speed onto the belt must be as low as is humanly possible.

I did a conveyor for lumps which weighed about half a ton each.

The chute design was therefore critical, but it worked. This surprised me, as according to Larry I should not be normally capable of anything (due presumably to a sheltered life).

For details of loading big lumps onto belts, please refer to my paper presented at Beltcon 13. This may have some relevance.

It was published in Bulk Solids Handling volume 25 :2005

Regards

LSL Tekpro ■