4.2. Summary of Loading Methods

So, once the loading of scraper 1 is completed, the pusher will back-track and spot the next scraper, scraper 2, and start pushing it in the same direction. So, that is what is a back-track loading. So, first it is pushing the scraper 1, as a scraper 1 is completely loaded it will start moving on its own. Once the scraper 1 is loaded, your pusher will get detached and return that is backtracking.

The back-track loading method involves the pusher detaching from a fully loaded scraper and returning to get the next scraper. In this case, the pusher must physically return to the previous position to pick up the next load, which adds time to the overall process.

Think of this method like a train that must go back to its starting point to pick up more passengers. Once one train carriage is full, it must return to the station before picking up the next carriage, leading to longer waiting times for all the passengers.

One limitation of this back-track loading method is it needs additional time for returning back. Therefore, we call this the slowest method. The return time is more because of backtracking, which means it takes longer for the pusher to complete its cycle.

The back-track loading method is considered the slowest due to the extra time required for the pusher to return to its original position after loading the first scraper. While this method is popular, it creates inefficiencies due to longer waiting times.

Imagine waiting for a taxi that leaves the airport after dropping off one passenger. The taxi cannot pick up another passenger until it returns to the airport, making every trip longer, similar to the delays caused by the back-tracking process.

The next method which we are going to discuss is your chain loading method. This is commonly followed for long, narrow cuts like roads. The pusher is pushing the scraper 1, once a scraper 1 is completely loaded, the pusher will get detached from the scraper 1 and the pusher start pushing the next scraper.

In a chain loading method, the pusher does not need to return to the original loading point. Instead, after loading one scraper, it moves directly to the next scraper that has moved into position. This significantly reduces the return time and allows for a faster overall cycle.

This can be likened to a delivery truck stopping at multiple houses on a single block. Rather than returning to the depot before continuing to the next house, the truck simply proceeds to the next delivery, saving time.

The next one is shuttle loading, this is not commonly followed, but you can follow it when you have two fill areas. What happens here is the pusher is pushing the scraper 1, and after that your pusher is getting detached from the scraper 1 and it starts pushing another scraper in the opposite direction.

The shuttle loading method is used when two fill areas exist, allowing scrapers to move in both directions. This set-up enables the pusher to switch from one scraper to another without returning to the starting point, leading to reduced cycle time.

Think of a sports team where players pass the ball back and forth to each other instead of one player running back to a central point after every play. By keeping the action moving in both directions, they can play more efficiently and effectively.

When you compare all these 3 methods, you can see that your back-track is the slowest method. The cycle time is relatively higher because it has to backtrack or return to support the next scraper, but your chain and shuttle loading, though they are not commonly followed, have lesser cycle time.

In summary, while back-track loading is the most common method, it is the slowest due to needing return trips. Chain and shuttle loading methods are faster because they minimize the time lost in returning to pick up scrapers, making them more efficient alternatives in certain situations.

Visualize a bus route: a bus that makes frequent returns to the station (back-track loading) will have longer total travel time compared to a bus that can drop off passengers continuously along the route without returning to the station until the end of its shift (chain and shuttle loading).

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