1. Productivity of Shovel

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 degree. So, the truck is placed at 90 degree, this will be 90 to the bucket position. So, this is a common position. So, basically angle of swing is nothing but the horizontal angle between the digging and the dumping position between the loading and the dumping position.

When using an excavator, positioning the truck nearby is crucial due to poor mobility of the equipment. Ideally, the truck should be at a 90-degree angle to the excavator's bucket position, allowing for efficient loading. The angle of swing refers to the horizontal angle formed between where the digging occurs and where the material is dumped. Keeping the truck close reduces the time spent swinging the bucket, thereby increasing productivity.

Imagine trying to hand someone a cup of water from across a long table versus passing it directly to them. The direct handoff (like keeping the truck close) is quicker and more efficient than stretching to reach it (like swinging the excavator's bucket further).

As the truck moves further away, your angle of swing would increase. As the angle of swing increases, you can see that your cycle time will increase, the productivity will decrease.

The angle of swing directly affects how long each cycle of loading takes. When the truck is positioned farther away, the excavator's bucket must swing a larger arc to reach the truck, leading to longer cycle times. Consequently, as cycle time increases, productivity decreases since less material is loaded in a given period.

Consider a swing at a playground: the farther away you push off (the farther away the truck is), the longer it takes to come back to the starting point (loading). Keeping the swing close allows quicker and more efficient motions.

Ideal condition ideal production of shovel is based on 90 degrees swing that is what I told you, the truck will replace it 90 degree is ideal condition and the actual height of cut in your project site should be same as optimum height of cut.

For shovels to operate at optimal productivity, the angle of swing should ideally be maintained at 90 degrees. Additionally, the actual height from which material is being cut should match the optimum height determined for the specific machine. This ensures that the machine operates at maximum efficiency, reducing the need for corrections that would otherwise lower productivity.

Think of it like baking a cake: there’s a perfect temperature and time for baking (similar to the 90-degree angle and optimum height). Deviating from those can lead to a cake that's either undercooked or burned, just like suboptimal angles and heights affect the efficiency of the shovel.

Now, let us see what are all the adjustment factors, we have to apply while doing the productivity estimation based upon the height of the cut of material actual height of cut of material in your project site and based upon the angle of swing that is going to depend upon the position of your truck relative to the position of your excavator.

When estimating the productivity of a shovel, it's important to account for adjustment factors. These include the actual height of the cut compared to the optimum height, and the angle of swing created by the distance and position of the truck. If there’s a discrepancy between actual and optimal conditions, corrections must be applied to maintain realistic productivity estimates.

Like adjusting a recipe depending on the ingredients you have (i.e., if you don’t have as much flour as needed, you adjust other ingredients). Similarly, if the height of cut differs from the optimum, adjustments in productivity estimations are essential.

If the actual height of cut is same as optimum height of cut, it means the percentage is 100% how do you calculate the percentage actual height of cut divided by optimum height of cut for the particular machine.

A correction factor is applied when actual conditions deviate from ideal ones. If the actual height of cut equals the optimum height, the productivity percentage is 100%. This is calculated by dividing the actual height by the optimum height. If the height is less or more than optimum, a corresponding correction factor must be applied, as this will impact productivity significantly.

Think of it like a score on a test. If you get everything right (100%), you don’t need any extra points (corrections). But if you miss some questions, you adjust your expectations based on how many you got right versus what was possible.

Another thing to be noted is truck spotting clearance. That means, as I told you, it is preferable to place a truck closer to the excavator. But at the same time, note that there should be some space left for the tail swing of the shovel.

While it's beneficial for productivity to place the truck near the excavator, ensuring there's enough space for the excavator's tail swing is crucial. This prevents any accidental collisions and allows for full movement of the machinery without obstruction, which is crucial for maintaining efficiency on the site.

Imagine driving a large truck in a tight garage. You want to park as close to the door as possible, but if there’s no clearance to open the door without hitting the wall, it creates a problem. Similar clearance for the excavator ensures smooth operations without interruptions.

Other important factor is haul unit exchange time. That means the time needed for the loaded truck to leave its position. And for a new truck that is an empty truck to take the position.

Haul unit exchange time plays a significant role in productivity, referring to the time needed for a truck that’s just been loaded to exit and for an empty truck to take its place. Effectively managing this exchange minimizes downtime, allowing for continuous loading and improving overall productivity on site.

Think of it as a relay race; if the outgoing runner takes too long to pass the baton to the incoming runner, the team loses precious time. The quicker the transition between trucks, the more materials can be moved efficiently.

Now let us see how to estimate the productivity of the shovel. So, for all these machines, the principle is going to be the same...

Estimating shovel productivity involves calculating the volume that the bucket can carry, known as the heaped volume, and adjusting based on the bucket fill factor to account for material type. This value is then divided by the cycle time or adjusted by the number of cycles per hour to get the productivity rate. Further adjustments are needed based on conditions like swing angle and height of cut, ensuring accurate estimations.

Consider it like managing a restaurant's output. You need to know how much each chef can cook per hour (capacity), how long each dish takes (cycle time), and adjust for busy days or special menus that may affect those times. Keeping track of this helps efficiently serve more customers.

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