Submit an interesting question to the board and we’ll circulate it to our members who are most knowledgeable on weighing and sampling and post the answer here. Send your question by email to info@nwsassn.org.

Question

When a set of rail cars are loaded and weighed at the mine and delivered some distance to a plant how much rain is allowed in the rail cars before a material test on a belt-conveyor scale is aborted and what type of gauge can be used?

Answer

The rule of thumb is 1/4 inch of rain. 

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Q20.  Have a client that is working on a DRI (Direct Reduction Iron) project that will have a sampler and wants to know if there is any specification etc for DRI.  Can you forward me any information you can get on this subject.

Question19:  If a belt-conveyor scale manufacture wants to sell belt-conveyor scales in Canada for legal for trade or non-legal for trade (general purpose scales for blending, process control etc) is there any requirements like CSA, ISO 9000 etc?

ANSWER:  Applicable Electronic equipment must be CSA approved or by an accredited agency, conforming to the Canadian Electrical

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Question18:   Does Canada have a similar requirement as the US for legal for trade belt-conveyor scales and if so do they have more than one accuracy class?

ANSWER:  Yes, Canada does have a legal for trade program for belt-conveyor scales but unlike the US they don’t require a permanence test only the laboratory and initial field

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Question17:   How can a 144,000 lb hopper scale with a 50 lb division and 18,000 lbs of test weights be called a 0.1% acceptance or 0.2% maintenance tolerance scale when 50 lb divided by 18,000 lbs = 0.28%?

A user is taking hand samples at his power plant; the mine is taking mechanical samples at the mine. The user thinks the coal he is getting isn’t per the contract and wants to take the mine to court. Would the court accept hand sampling as a legitimate method of sampling assuming the

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Q16:  During a discussion with a client,  the question came up as to why are sampling manufacturers changing from the standard three roll idlers under the sweep sampler to multiple rolls, when all the manufacturers have said bias tests have proved no bias with the three roll idlers.  I understand one of the reasons was

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Q15:  Is a Coupled in Motion (CIM) double draft track scale, if used with cars un-coupled, an acceptable reference scale used to material test a belt-conveyor scale? Over the years double draft track scales have been used successfully for material testing belt-conveyor scales.  The State said no, and I was surprised because I have used the CIM double draft in

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Question 14

Based on your experience, would you see any moisture bias of commercial significants if the primary sweep sample dropped approximately 45 ft to the  feeder feeding the crusher and secondary sweep module?

Answer

No. Manufacturers with experience testing their systems for bias, do not routinely have any problem passing the bias test with well-designed sampling piping. Sample Techs

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“We would like to know if we weight the material on different weighing scale, will it show different weights? Steel components weigh less than or equal to 500 grams when weighed on jewelry shop. When weigh on grocery shop. When weigh on weighing scale in technical laboratory. When weigh on weigh scale for the heavy material (truck/transport

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