Originally Posted by johngateley

I seem to be losing it. About twenty minutes ago I had replied to a thread blasting the usefulness of Health and Safety. It still stands.

Now, consider that nearly all plants, wherever and whatever, clearly state in new specifications that they implement a noise limitation criterion. This is usually set at 85dbA in line with local statutes and is quite universal. Whether it is, or can be, adhered to is another matter. In the case of persons working in the proximity of comminution machinery the maximum allowable sound pressures are very likely to be exceeded by a large margin. Ear protection for those persons is mandatory so the instrumentation referred to is going to be mandatory as well. So can you please tell the forum members where sensors are not accepted so that those plants' alternatives can be discussed?

In design audits I always come across the chapter in the specification regarding noise limitation. All Contractors swear compliance: often in the face of overwhelming ignorance of the situation. I am rarely sullied by those penny pinching contractual squabbles at the hand over stage but if I was involved I would find it very easy to pursue claims for excessive noise levels.

wow!

sorry but i think i didn't explain the issue clearly!

I am talking about sensors that monitor SAG mills noises and measure such operating parameters like balls filling in mill and preventing of the damage caused by grinding Ball collision to Mill inside liner . In fact my question topic isn't HSE, it's about monitoring Mills.

But anyway, John thanks for the answer. it was interesting ! ■

Originally Posted by johngateley

I am fully aware of the noise issues in mills. Whatever the usefulness of sensors might be I was trying to explain that they are somewhat obligatory simply because the operators must wear ear muffs and therefore cannot properly hear the balls clouting the liners. So for legality within liner life it seems that sensors are the best option.

It is essential that monitoring is done safely in this day and age. Your statement that some plants don't accept them suggests that you are aware of plants where operators are exposed to prolonged excessive noise levels. So can you please tell the forum members where sensors are not accepted so that those plants' alternatives can be discussed?

Hi John

I totally agree with you on obligatory noise sensors.

but the sensors I was talking about for protecting mill liner is different than "noise control for ear protection" sensors in their role.

In fact sensors for protecting tumbling ball mill liner are not accepted, because different noise from other devices interfere with Mill noises. ■

Dear Mr. Qaredaqi,

you are surely aware that noise sensoring is but one of several technical prinicples that are used in order to get " a picture" out of the mill. However, the input being very complex (all those different parameters) + the variations due to different mill input make that an issue to be decided before contracting and then on delivery to be fine tuned on site. I think there's no "remote control" answer, you'd probably better define clearly your application & needs, hire someone out of that field as consultant and invite some reputable suppliers to have a look into your premises.

"Useful" is quite large a word.

If something is not accepted, there would be some reason and if you are in that business you probably have the feel of that, don't you?

Technically, as far as i. k.:

Ambient sound level is one of the main downs of the "electronic ear". Shielding might work, but cf. above.

If the base principle is the check of an startup noise level against a finished state noise level, this might work for rubber lining too, only that noise level shall decrease instead of rising again as when balls start to hit metal lining / or show some other specific behaviour.

So make up a specification, check personally a reference of the supplier in a similar application & bind the supplier into the warranty on system performance.

Regards

R. ■