Question$1$: PARTICLE SIZE DISTRIBUTFONS

You take a sample from one of the streams in the crushing circuit and use a series of lab screens to split the sample into $5$ heaps shown below. The largest particles in the sample are $50mm.$ The diagram below represents the result of a laboratory sieving operation $($also called a screening or sizing analysis$)$ done to determine the size distribution of a sample of particulate material. Each heap of particles has been removed from the screen used to sort the particles according to their size. Each heap is a size class defined by the screens used to create the heap.

Note the order in which the particle size classes have been labeled $-$ largest size class $=$ size class $1.$

Each size class is defined by a max and min size $-$ i$.$e$.$ the upper $($or top$)$ and lower $($or bottom$)$ boundaries of the size class $-$ and which are defined by the screens used to make $0$create the heap. Identify the top & bottom size class boundaries of each size class. Note $($a$)$ that the bottom boundary of one class is the top boundary of the next smallest size class, $($b$)$ the convention $\text{'}-35+24mm\text{'}$ means particles with a size less than $35$ and greater than $24mm.$

The CUMULATIVE SIZE DISTRIBUIION: This is a more convenient way to describe size distributions. It refers to only one screen or size and indicates the proportion of the particles in the sartaple that are smaller than a particular size and so will pass through a screen of that size. In effect, the $\%$ passing a given size will be the 'accumulation' of all the size classes that are smaller than that size, hence the term 'Cumulative Distribution'.