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I was wondering this also -- what could a ship that sunk in 1917 have in its hold that would be worthwhile to salvage 100 years later? For anyone knowledgeable

by FreakyT 12y ago

I was wondering this also -- what could a ship that sunk in 1917 have in its hold that would be worthwhile to salvage 100 years later? For anyone knowledgeable about this field: Are these sorts of late salvage operations typical?

fit2rule 12y ago
Steel not polluted by atomic-age testing?
- mikeash 12y ago
  And just to be clear, that's totally a thing and not at all crazy. See: http://en.wikipedia.org/wiki/Low-background_steel http://en.wikipedia.org/wiki/Low-background_steel It's really, really, really hard to produce steel without any atmospheric contamination. Salvaged ships built before the beginning of atmospheric nuclear testing are the main source of steel that isn't contaminated with radioactive material.
- achr2 12y ago
  Your comment led me to look up low-background steel. Very interesting thanks.
oh_sigh 12y ago
Someone else mentioned low-background steel. I wanted to note that old lead is also valuable because it has had time for most of the (naturally occurring) radioactive PB-210 to decay(half life: 22 years)
- mikeash 12y ago
  Do you know just what causes Pb210 to accumulate before the lead is mined but stop doing so afterwards? I was going to mention that but couldn't find anything that discussed just what was going on.
  - dgemm 12y ago
    It's part of the decay chain of U238 which is present in trace amounts in much of the earth's crust. I would imagine it's nearly impossible to chemically separate it from the lead. Would require a process similar to that used for enrichment of U235 but economically not worth the cost.
    - mikeash 12y ago
      So basically: lead mixes with trace amounts of uranium. Refining removes the impurities, including uranium. However, the uranium leaves behind trace-r amounts of lead-210, which refining cannot (easily) remove. So your choice is to carry out expensive isotope separation, wait a couple hundred years, or find someone who refined the lead long ago so you don't have to wait. Is that about right? For some reason I thought that being shielded under deep water was part of the deal, which confused me. Don't know where I got that idea.
dgemm 12y ago
There are many billions in lost treasure alone on the ocean floor. "Late" salvage is not typical but also not unusual as technology makes it easier to find and possible to recover wrecks. Legal obstacles seem more difficult than technical ones these days. See Odyssey's legal battle vs. Spain for example.

by FreakyT 12y ago

fit2rule 12y ago

Steel not polluted by atomic-age testing?

mikeash 12y ago
And just to be clear, that's totally a thing and not at all crazy. See: http://en.wikipedia.org/wiki/Low-background_steel http://en.wikipedia.org/wiki/Low-background_steel It's really, really, really hard to produce steel without any atmospheric contamination. Salvaged ships built before the beginning of atmospheric nuclear testing are the main source of steel that isn't contaminated with radioactive material.
achr2 12y ago
Your comment led me to look up low-background steel. Very interesting thanks.

oh_sigh 12y ago

Someone else mentioned low-background steel. I wanted to note that old lead is also valuable because it has had time for most of the (naturally occurring) radioactive PB-210 to decay(half life: 22 years)

mikeash 12y ago
Do you know just what causes Pb210 to accumulate before the lead is mined but stop doing so afterwards? I was going to mention that but couldn't find anything that discussed just what was going on.
- dgemm 12y ago
  It's part of the decay chain of U238 which is present in trace amounts in much of the earth's crust. I would imagine it's nearly impossible to chemically separate it from the lead. Would require a process similar to that used for enrichment of U235 but economically not worth the cost.
  - mikeash 12y ago
    So basically: lead mixes with trace amounts of uranium. Refining removes the impurities, including uranium. However, the uranium leaves behind trace-r amounts of lead-210, which refining cannot (easily) remove. So your choice is to carry out expensive isotope separation, wait a couple hundred years, or find someone who refined the lead long ago so you don't have to wait. Is that about right? For some reason I thought that being shielded under deep water was part of the deal, which confused me. Don't know where I got that idea.

dgemm 12y ago

There are many billions in lost treasure alone on the ocean floor. "Late" salvage is not typical but also not unusual as technology makes it easier to find and possible to recover wrecks. Legal obstacles seem more difficult than technical ones these days. See Odyssey's legal battle vs. Spain for example.