If samples selected for the testing program present large rocks, they must be crushed. Basically at the beginning of this stage the objective is to reduce the particle top size without generating excessive quantities of fine material by performing repeated crushing-screening operations. The minimal equipment required is a jaw crusher at ½” opening, cone crusher at ¼” opening, roll crusher screens at different sizes.
It is fundamental to be sure all equipment is clean and in good condition. Once the ore sample arrives to be lab, it must be identified and weighted. If the sample is wet, it has to be dried prior to crushing and screening. Now, if the sample has particles coarser than ½”, pass the entire sample through the jaw crusher followed by screening at 10 mesh or other size according to the tests to be done. Then, crush the oversize material in the cone crusher followed by screening. If there is any particle coarser than 10 mesh, crush the material until no oversize exits. Employ the roll crusher when is necessary. If the sample is finer than ½”, separate the part of the material by screening the material at 10 mesh.
Jaw Crusher Cone Crusher
Next step is to mix the sample in order to get a homogeneous sample prior to splitting into test charges. The equipment needed is a flat shovel, broom, Jones Riffle splitter and a rubber rolling mat. If the weight of samples is less than 50 kg, carefully dump the sample to be blended in a conical pile onto the center of the clean floor area. Now, with the shovel in hand, walk around the sample pile and try to flatten the pile to five or six inches in height, divide the sample into four quarters, take opposites quarters into two piles and with the broom collect the fine particles equally between the piles. One more time, with the shovel flatten the two piles and recombine both by taking alternate shovelfuls of sample and flatten the pile and split into four quarters taking opposite quarters to form two piles. Repeat the coning and quartering procedure for ten times until to be sure the blending and homogenization is good.
It is possible to employ the Jones Riffle splitter. In this case, split the sample into two parts and take each part and again split into two parts. Combine two quarter parts and split into two parts. Combine the other two quarter parts and split into two parts and take one part from the two latter samples, combine them and split into two; take the other portions, combine and split into two parts. Repeat the last two steps in order to have a good blending. Combine the entire sample back together if required.
If there is not much weight of ore sample, the mat rolling technique may be employed. For example if there is 10 kg or less, carefully dump the -10 mesh sample onto the center of the mat, grasping diagonally opposite corners of the mat, slowly pull one corner towards the opposite corner causing the sample to roll itself and pull the other corner towards the first corner causing the sample to roll back itself. Repeat this rolling action with the two opposite mat corners being carefully to give a good blending of the sample.
Jones Riffle Splitter Vibratory Ring Pulverizer