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The value of a coal cargo is determined by testing a sample collected manually or by a mechanical coal sampling system. If the sampling method or the sample preparation is biased or inconsistent, the value of the cargo can be inaccurately or imprecisely determined. These results in the cargo being over or under-valued, and the buyer or seller is then erroneously compensated for the value of the cargo. Expensive, wrong decisions can be made based upon biased, incorrect, or erratic data.
SGS will work closely with your staff to insure the highest practical work with the minimum practical interference with your operations. SGS provides the accurate technical expertise to allow you to know the exact quality of coal that you have. SGS focuses on four specific types of sample testing, which includes:
System Inspection
A first step in any evaluation of sampling system operation is a thorough inspection. SGS engineers and technicians are trained and equipped to do complete inspections of pneumatic, hydraulic and electric drive components, sample cutters, chutework, crusher components and PLC function. Cutter speeds applicable to falling stream cutters and belt speeds applicable to cross belt cutters are measured, as well as cutter operating intervals. With this data a sample extraction table is prepared and the design sampling ratio calculated on an “as-is” basis.
The client is provided a report of deficiencies and recommendations for improving sampling system performance, and reliability while lessening the possibility of biased sample collection.
System Bias Testing
SGS is the clear leader in bias testing of mechanical sampling systems, both in number of tests conducted annually and in the superiority of techniques employed. Performing a test for bias is not an “experiment” for SGS people. Technicians come to the job site fully prepared and equipped with the proper tools, collect the test samples with minimal disruption to client operations and issue a report with the test results without delay.
SGS also designs and conducts tests to meet special requirements, including bias tests of auger sampling systems and tests for bias of mechanically collected samples used to determine coal size distributions. The latter generally require use of Hotelling’s T squared statistical methods in order to properly treat the typical variety of sieve sizes of importance to the client.
SGS uses a random numbering scheme in bias test set chronology for preparation and testing in the laboratory in order to assure no there is no false indication of failure of mutually independence for the test results. |
