Which stockpile method is noted for its high cost and slow process?

The clam shell stockpile method is characterized by its high cost and slow processing time. This method involves using a clam shell bucket attached to a crane or excavator to scoop material and stack it in a desired configuration. The nature of this method means that it requires specialized equipment and manual operation, leading to increased labor costs and a longer duration to complete the stockpiling process.

In contrast, other methods such as the elongated cone and mini stockpile techniques often allow for more efficient and cost-effective stockpiling due to their simpler mechanics or lower resource requirements. The mechanical splitter also provides an efficient and standardized method for dividing materials without the need for extensive manual handling, thus facilitating a quicker operation at a lower cost. Therefore, the clam shell method's reliance on heavy equipment and manual labor significantly contributes to both its high cost and slower process compared to other stockpiling options.