The key to determining the total moisture content is to maintain the total moisture content during coal sampling, and no loss is allowed. Therefore, the operating requirements are as follows: 1. The full moisture coal sample taken should be stored in a well sealed container and in a cool and dry place. 2. The sample preparation speed should be fast, and it is best to use a sealed crusher. 3. When preparing full moisture coal samples, it is required that they should not be too fine. If a finer coal sample is needed, a sealed crusher sample should be used, or a two-step method should be used for full moisture determination. 4. Total moisture is a standardized measurement item, therefore, it is necessary to strictly follow the requirements specified in the standard for operation. 5. The total moisture should be measured immediately after being sent to the laboratory. 6. Before weighing the coal sample, the coal sample in the sealed container should be mixed for at least 1 minute before weighing.