Weathering: Refers to the condition of the particle or stockpile
|
Impurities/Weathering |
Desirable |
Potentially Objectionable |
|
Physical and chemical condition due to weathering, alteration |
Insignificant changes in texture, structure, com position; reactive products absent |
Significant changes in texture, structure, composition; reactive products or physically harmful products present |
|
Surface of particles |
Fresh, clean |
Weathered, "dirty," coated with clay minerals, rock dust, organic matter |
|
Contaminants |
Non or a few slightly harmful contaminants present |
Large amounts of objectionable or few very objectionable contaminants present (e.g., sulfates; opal) |
|
Material finer than75 pm = "fines" |
Small, physically or chemically not harmful |
Large amounts, physically and/or chemically harmful |
