<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>gallium, indium, tantalum, hafnium and zinc, these are very important elements, but they are not the only ones that are in short supply. A while back I read that 50% of all the mine-able copper was already out of the ground & in use or in garbage dumps, & the rate of mining more is speeding up. Platinum could be used in inexpensive power cells that operate with alcohol if there was more of it available.Recycling will only get us so far. We need to start asteroid mining now. <br />Posted by boris1961</DIV><br /><br />Still, there is no evidence that any of these elements can be reached at less expense than they could be obtained from the low concentrations on the earth's surface. "Running out" does not usually mean there's none left, it means it's no longer economically worth it at the present time. If the price goes high enough, even low grade ores will be worth it, while mining mission to asteroids might cost 10 or 100 or 1000 times as much, with (so far) no guarantee of success, and no indications the elemental recovery would cost less than working our surface harder. </p><p> </p><p>Let's remember, so far we have visited a half dozen asteroids close up. Most provided little elemental composition data. The mission to visit the largest ones (Dawn) won't be conpleted for another 7 years.</p><p>Who's going to shell out more than NASA's annual budget (~ 17 $billion a year) to plan such a mission with not even a hint of a profitable payoff at the end?</p><p>I know, having a pragmatist is a pain, but it's my job, apparently... <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-smile.gif" border="0" alt="Smile" title="Smile" /></p><p> </p> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>