3. Haul Time and Return Time

But the loading time will be number of bucket loads multiplied by the bucket cycle time.

Loading time is calculated based on how many bucket loads you're moving and how long each load takes to be loaded. To find loading time, you simply take the total number of cycles (bucket loads) and multiply it by the time it takes to load each bucket. This helps in planning how long it will take to fill a truck or container needed for transport.

Imagine you're filling a bucket with water from a well. If it takes you 2 minutes to fill one bucket and you need to fill 5 buckets, your total loading time will be 10 minutes. This principle applies in construction where machines load materials into trucks.

For every machine what is this safe operating load in terms of weight is given by the manufacturer, so that we call it as a gravimetric capacity.

Gravimetric capacity refers to the maximum weight that a machinery can safely carry. Each piece of equipment, whether it's a truck or loader, has a manufacturer's specified limit. If this limit is exceeded, it can cause damage to the machine, leading to increased maintenance costs and potentially expensive repairs.

Think about carrying a backpack. If you fill it beyond a certain weight, it becomes cumbersome and can break. Just like you, machines also have weight limits to ensure they operate effectively without risking damage.

Check truck load is less than rated gravimetric payload.

It's crucial to ensure that the load weight in the truck is within the safe gravimetric capacity. This can be checked by multiplying the density of the material by the volume load to get the total weight. Overloading can lead to serious machinery failures and increased repair costs.

Consider a bus carrying passengers. If more passengers get on than the bus can handle, it may break down or have an accident. Similarly, if a truck carries more weight than it’s designed for, it can lead to breakdown or accidents.

But if the material is going to be denser like wet sand or other denser material, what happens is there are more chances that your machine maybe overloaded.

The density of the material being loaded affects the total weight and hence the loading practices. Heavier materials can lead to overheating and excessive wear and tear on machinery, making it crucial to monitor. Proper training about material properties can ensure that safe loading practices are followed.

Imagine trying to fit a heavier load of bricks into a truck versus loading in fluffy pillows. The bricks are denser and heavier, meaning you would have to be much more careful about how many you load in.

So, as we discussed earlier the dumping time will depend upon the type of hauling unit whether it is going to be rear dump or bottom dump or side dump accordingly the dump time will vary.

The time taken to dump the material from the truck depends on the type of dumping mechanism used—like rear, bottom, or side dump. Additionally, the nature of the material (whether it's sticky or heavy) and congestion in the dumping area also influence the total dumping time.

Consider pouring a jug of water. If the jug has a spout, it pours quickly (like a bottom dump). If there’s no spout, it takes longer and is messier (like a rear dump). Congestion at the site can be compared to trying to pour water in a crowded kitchen—you're blocked by other activities.

The return time is the same way using truck manufacturer performance chart, but here the truck will be in the unloaded condition, empty weight, and consider the resistances also.

To calculate return time, we refer to the performance chart when the truck is empty. The distance back to the loading site and any resistances such as gradients will factor into how fast the truck can return for another load. Generally, return time will be shorter due to the truck being unloaded, allowing it to drive faster.

Imagine riding your bike uphill to carry groceries—it's slow and difficult. But coming back down, you're much quicker because there's no load, demonstrating how weights affect speed.

So, balancing the capacity of the hauling equipment and the excavator bucket size will result in maximum loading efficiency, and reduce total cost.

Balancing the number of trucks with the excavators is crucial. Ideally, the truck's capacity should be four to five times that of the excavator's bucket capacity to optimize the cycle time and reduce waiting time. If the loads are balanced, both machines will operate at maximum efficiency.

It's like balancing the number of players on a sports team. If you have more players suited for offense but not enough on defense, your team won't perform well. Similarly, the correct balance between trucks and excavators leads to optimal performance on site.

--