3.1. Maximum Dumping Height and Digging Reach

They have poor mobility. So, that is why it is preferable to place a truck very close to the excavator. So, very commonly you can see that the truck is placed at 90 degrees. So, the truck is placed at 90 degrees; this will be 90 to the bucket position. So, this is a common position.

The placement of the truck is crucial for the efficiency of the excavator. When the excavator is working, it typically has poor mobility, meaning it can't easily move around. Therefore, to optimize the loading process, the truck should be parked very close to the excavator. The most effective angle for this setup is 90 degrees. This arrangement minimizes the distance the excavator needs to swing its bucket while loading, which can improve productivity.

Imagine trying to fill a bucket of water from a fountain. If you are standing close to the fountain, you can easily scoop out the water without stretching or moving too much. Now, think of the truck as the fountain and the excavator as the person filling the bucket. The closer the truck (fountain) is, the faster and more efficiently the excavator can load it.

Basically, the angle of swing is nothing but the horizontal angle between the digging and the dumping position between the loading and dumping position.

The angle of swing is the horizontal measurement that illustrates how far the excavator's bucket has to rotate to reach the truck from the digging position. A smaller angle means less time swinging and more efficiency. As the truck is placed further away, the angle of swing increases. This not only makes the loading process slower but also increases the cycle time, reducing overall productivity.

Think of a playground swing. If a child swings directly back and forth (a small angle), they can swing quickly. But if they start to swing side to side (larger angle), it takes more time to go back and forth. Similarly, the excavator works best with a smaller angle of swing for faster loading.

Now, let us see what are all the adjustment factors we have to apply while doing the productivity estimation based on the height of the cut of material and the angle of swing.

To accurately estimate productivity, certain adjustment factors must be taken into account. These include the height of the cut being performed and the angle of swing. If the actual height of the cut matches the optimum height, no adjustment is needed. However, if the actual height deviates from this ideal, or if the swing angle is more than 90 degrees, you must apply a correction factor to adjust your productivity estimates.

Imagine trying to fill a container with a specific amount of liquid. If the container is the right size, you don't need to pour the liquid slowly or adjust anything. But if it's too small or too large (like when the height of cut is not optimal), you have to adjust how you pour or the time it takes, much like how you adjust productivity estimates for excavators.

If the actual height of cut is the same as optimum height of cut, it means the percentage is 100%. If this percentage is going to be lower or higher, you have to apply a correction factor.

When estimating productivity, the relationship between the actual height of cut and the optimum height of cut is crucial. If the actual height is equal to the optimum (100%), no correction is necessary. However, if it's lower than the ideal height, or if the height exceeds the optimal by a significant margin, the productivity will be adversely affected, necessitating the application of a correction factor to adjust productivity calculations.

Think of baking a cake. If you use the right amount of sugar, the cake turns out perfect. If you use too little sugar (lower height of cut), the flavor might be bland, and you need to adjust your recipe positively with more sugar (applying a correction factor) to improve the taste.

As I told you, it is preferable to place a truck closer to the excavator. But at the same time, there should be some space left for the tail swing of the shovel.

While it's best to position the truck close to the excavator, safety must be considered. There needs to be enough clearance for the tail of the excavator to swing around without hitting the truck. This clearance is essential to avoid accidents and ensure that the excavator can operate smoothly without obstruction.

Imagine a large pendulum swinging in a small room. If it swings too close to the walls (the truck), it might hit something. By ensuring some space, the pendulum can swing freely without danger. Similarly, ensuring clearance for the excavator's tail keeps operations safe and efficient.

The total time required for the loaded truck to clear its loading position and for the next empty truck to take the position for loading. This is also going to affect productivity.

The time it takes for a truck to load and then leave, making space for another truck, is known as haul unit exchange time. This duration can significantly impact productivity. If resources (trucks) are not available quickly enough for the excavator, it causes delays that reduce efficiency. By minimizing this time, operations can maintain a steady workflow.

Consider a game of musical chairs: If the music stops and you're not quick enough to find a chair (the truck), you have to wait longer than you'd like. In construction, the faster each truck can leave and be replaced with an empty one, the better the loading process flows.

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