Later in the winter the amount of coal stock is lower in the sizes of rice and nut. For the breakers to meet the demand, they use rice grinders. Mine run rice is a more uniform size. When the supply is getting low, breakers mix Buckwheat and Pea, and grind to produce rice. It is then ran through rerun tables in the breaker. Unfortunately, grindings are a dirtier mix, and the sizing is a bit more rough. Most breakers have a screen one size larger on the rerun side for rice. That allows for the majority of coal to be collected in the rice bin. Although the piece of coal may look like Buck or Pea in length, check the thickness. Grinders are double wheeled, and sometimes just split the coal length wise. Which is a drawback for grindings. We ask or customers if grindings are ok, or if they would like to wait for mine run rice. If the rice grindings came from a stove grinder, they normally look more uniform. Due to the larger piece of coal being ground. Unfortunately, when you grind 20 ton of stove you make a majority of nut and only about 2 ton of rice. So a rice grinder is more economical for a breaker. I know that doesn't solve the unpleasantness you get from opening the bag and seeing that, but it's a bit of an explaination for the mix of sizing.