The average cost of excavation is approximately $3,200, with typical projects ranging from $500 to $15,000. Depending on the contractor, you may be charged between $50 and $200 per cubic yard or an hourly rate of $40 to $180 for an excavation specialist. The total cost is influenced by several factors, including the project size, the amount of soil to be removed, and the soil's condition. Hard soil, tree roots, or excessive rocks and clay can increase the price, potentially adding $200 to $1,200 to the final bill. Other factors that can drive up costs include the presence of nearby structures that complicate the work or tight spaces that require manual excavation instead of heavy machinery.

There are several methods to hollow out a tree stump, and the best one depends on your tools, experience, and priorities. Common methods include using a chisel and hammer, a chainsaw, or burning.

• Chisel and Hammer: This is often considered the easiest approach for those with limited tools or experience, though it is the most time-consuming.

• Chainsaw: Using a chainsaw is the fastest method, but it comes with significant safety risks, especially for inexperienced users.

• Burning: This can be an effective method, but it is not recommended unless you can first drill holes into the stump. Without holes, the stump will be difficult to light and may not burn completely through.

A power drill with at least a ⅜-inch diameter bit can make the job quicker and easier, regardless of the primary method. While you can use a chisel or chainsaw without a drill, it will require more time and effort. Always wear protective goggles and thick gloves, as splinters are an inevitable risk.

A mini excavator can dig between 5 and 11 feet deep, depending on the type and size of the mini excavator. Mini hydraulic excavators are more powerful and can reach deeper into the earth, but electric models have a more limited range. Mini excavators over two tons in size are also more powerful and able to dig as deep as 11 feet.

A perc test can take anywhere from one to eight hours to complete. The total time depends on factors like the amount of excavation required, the depth and width of the holes, and whether multiple test holes are needed. For a single hole, the process of filling it with water and monitoring the drainage rate usually takes less than an hour. Professionals can often complete the entire test in a single day. While it's possible to get results the same day, some companies may take a few days to provide the official report.