Dear Shaklee:

There are other factors that need to answered before picking a number:

1. Dust control

2. Product degradation

3. Product properties that are a part of the wear equation - size, density, sharpness, shape, moisture, et.al.

4. How long you wish the belt to last

5. Height of loading onto the belt

6. Length of loading zone and spread of ore

7. Ability to preload fines before coarse

8. Chute design to minimize drop distance and maximize horizontal velocity to receiving belt and its texture

9. Loading uphill or downhill and degree of slope

10. Probably more items that do not come to this limited time and mind .....

Thus, no simple answer - more to know. ■

I do agree with the long length be a justification for the higher speeds, that is, the longer cycle time defrays the carrying cover wear due to material loading. The longer length and the investment also easily justifies the special attention to the transfers required for the higher speed of operation including clean up belts that will transfer scrapings back to the transfer. However it is minimizing the high investment cost that drives the high speeds, thus narrower belts for the required rate. Indeed ample storage is typically required at both ends so that the long overland conveyor may run continuously 24/7 in spite of the discontinuities of the source operations. Indeed some long overland conveyor projects are not economically (CAPEX) viable at slower speeds.

Joe Dos Santos ■

Yes, an arguement can be made for length and speed. Longer lengths may allow for higher speed due to the influence of belt wear and number of cycles through the tail loading station. In most instances, belt wear is highly attributed to ore turbulence at the loading station. As the belt length increases, belt wear will drop as noted. In most cases, the speed should be of a reasonable rate depending on the belt transport rate. You note 3.4 m/s. This is a very modest rate and applicable for in-plant systems less than 500 m in length. Transfer chute design becomes imperative to get right to control the wear factor. ■

You identify 3 lengths 27 m, 260 m and 240 m. What is the relevance?

Are you asking that they will not synchronously stop together without brake control, or special inertia enhancements, and that the small 27 m length belt loading station might plug?

Yes, the loading station on the 27 m conveyor might plug or it will become overloaded from the stopping action and cause spillage after the restart.

Your information is not sufficient to say so. Most of us will not do the math gratus to prove this point. ■