1.6. Problem Example on Production Estimation

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

In this chunk, we discuss the optimal placement of a truck in relation to an excavator. The ideal angle of swing is 90 degrees, meaning the truck is directly next to the excavator. If the truck is positioned further away, the angle of swing increases, leading to longer cycle times and decreased productivity. Essentially, the cycle time refers to how long it takes for the excavator to dig, swing, and dump the material. When the truck is too far, the machine has to swing more, which takes extra time and reduces the number of cycles it can perform in an hour.

Think of it like playing a game of basketball. If the hoop is right in front of you, it's easy to shoot the ball directly into it. But if you have to take a few steps back and shoot from farther away, it takes more time to aim and shoot, and you're likely to miss more often. Therefore, keeping the hoop close (or in this case, the truck) allows for more successful 'shots' (or work) in the same amount of time.

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. So, adjustment factors for the height of cut and the angle of swing for the shovel. If the actual height of cut is same as optimum height of cut, it means the percentage is 100%.

In this chunk, we introduce adjustment factors that influence productivity estimates. These factors account for variations in the actual height of cut and the angle of swing, relative to the ideal conditions. The optimum height of cut is essential for determining how effective the machine will be. If the actual height matches the optimum height (which is considered 100%), then no adjustment is necessary. However, if the actual height differs from the optimum, like being less or greater than that, productivity will be impacted, and we need to apply a correction factor to adjust estimates accordingly.

Think of baking a cake. If you have exactly the right amount of ingredients, your cake will come out perfectly (100% efficiency). But if you either use too little flour (which makes it collapse) or too much (which can make it rise unevenly), the final cake won’t be as good. Similarly, achieving the 'right balance' of height and angle for the excavator ensures optimal performance, just like your cake needs the right proportions to taste good.

For the angle of swing, when the angle of swing is more than 90 degree, you can see that the correction factor is reducing, it shows that your productivity will reduce, but if your angle of swing is lesser than 90 degree, you can see that the correction factor is increasing. That means it shows that your productivity is increasing.

Here, we focus on how the angle of swing affects productivity. If the angle exceeds 90 degrees, the correction factor decreases, indicating reduced productivity – the machine takes longer to swing to dump material. Conversely, if the angle is less than 90 degrees, the correction factor increases, suggesting higher productivity. This means that achieving a swing angle smaller than the ideal allows the machine to work more efficiently, reducing cycle times.

Imagine a dancer doing a turn. The more they turn, the longer it takes for them to face the audience again. If they keep their turn small, they can face forward much more quickly and smoothly. In excavation, just like in dance, keeping the swing tight improves performance.

Now let us see how to estimate the productivity of the shovel. The production of shovel depends upon the heaped volume of your bucket, heaped volume of your bucket you can get it from the manufacturer, that you are going to adjust with the bucket fill factor, depending upon your material type, then divide it by the cycle time.

This chunk explains the process of estimating shovel productivity. The productivity is initially calculated based on the heaped volume of the bucket, which is provided by the manufacturer. This volume must be adjusted by a bucket fill factor – this is based on the material being handled (for example, gravel might fill the bucket differently than heavy rocks). Finally, this adjusted volume is divided by the cycle time to determine how much material can be moved in an hour.

Imagine you are filling up a backpack to carry items. The backpack has a set capacity (like the shovel bucket volume). However, if you try to pack it with soft pillows, you might fit more than if you were trying to fit hard books. The fill factor is like considering how well you pack it, and the time it takes to pack and carry the backpack is akin to the cycle time for the shovel.

Now let us work out a problem on the production estimation a crawler mounted shovel with a heaped bucket capacity of 3.44 meter cube is loading a well blasted rock. The bucket fill factor can be taken as 1, depending upon the material type, they are supposed to take the bucket fill factor, it is readily given to you in this question as 1. It is working at 3.18 meter high face.

This chunk introduces a practical problem for estimating production. It describes a crawler-mounted shovel that has a specific bucket capacity and fill factor and notes that it is operating at a specific height. Here, students can learn to apply the principles of productivity estimation by plugging in the values for bucket capacity, the fill factor, and cycle time to arrive at an estimate for shovel productivity in real-world scenarios.

Think of this as a math problem, where you have a recipe that uses exact measurements. Just like cooking, if you know the amount of ingredients (bucket capacity), how well you can mix them (fill factor), and how long you'll take to prepare the dish (cycle time), you’ll end up with a final dish (productivity) that you can quantify.

--