Which characteristic best describes modern diamond mining operations?

The characteristic that best describes modern diamond mining operations is large scale and extremely expensive. This is primarily due to the significant investments required for the establishment of extensive mining facilities, advanced technology, and compliance with stringent environmental regulations. Modern diamond mines operate on a scale that allows them to harness economies of scale, meaning they can extract diamonds more efficiently and profitably from large reserves.

Additionally, the cost associated with modern diamond mining has continued to rise due to various factors, including the need for sophisticated equipment to access deeper deposits, the expense of adhering to environmental protocols, and the costs incurred in exploration and development. As a result, the operation of diamond mines today typically involves large, industrial-scale operations that require substantial financial resources, thus marking them as extremely expensive endeavors.

While other options touch on different aspects of mining operations, such descriptions do not capture the primary characteristics seen in modern diamond mining, which are marked by scale and cost.