A baby blue whale drinks this many liters of milk per day:

showing a photograph would make this a hell of alot easier

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]

the cost of mining is extremely low compared to the money earned from mining, creating income to improve the environment.