This isotope is, however, extremely expensive to produce in usable quantities.

A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water.

Unfortunately, it's also extremely hard to produce in any sort of usable quantity.

Long Island contains a series of sand and gravel aquifers, geologic formations which can hold, transmit, and yield water in usable quantities.

In late 1987 and 1988, they produced small but usable quantities of poison gas.

Under optimum conditions fermentation starts within two to three days, and gives off usable quantities of gas after 15 to 20 days.

It's only available in usable quantities synthetically, they just have to patent it, sell it, make $$$$.

One official suggested that it might take eight months before the restarting of a reactor produces a usable quantity of tritium.

Crystalline male hormones had been extracted in usable quantities from male urine by 1903, but it represented an infection risk.

The hypothetical discovery of usable quantities of water on the Moon may raise legal questions about who owns the water and who has the right to exploit it.