Some speculation posted by idratherbstacking (William Silver on Facebook) about Omega bars and M & B mining and whether M&B mining really was the company that made the bars:
Company Name: M & B Refining. Commonly referred to as Omega.
Company Location: Las Vegas, NV
Company Information: Founded in 1969 and disappeared in the early 1970s.
A trademark was filed in 1969 for the 2nd generation logo.
https://gold-forum.kitco.com/showthread.php?116090-M-amp-B-mining-Omega-poured-bars-score : comment about 1st generation bars: “These are pre 1969 bars prior to the filing of the trademark “double line” stamp that was used from '69-'74 when production stopped because of the sudden death of the owner of the company.”
“originally advertised and sold by Danny B. Crabb Coins out of Van Nuys California (as per COINage magazine, February 1970 pg. 19)”
Known sizes: Universaro 1 oz round, numerous bar sizes with a large variety of stamp and text placements
Gallery:
| Obverse | Reverse | Additional | Description |
|---|---|---|---|
| 1 oz round | |||
| 1st gen 1 oz | |||
| 1st gen 2 oz | |||
| 1st gen 3 oz | |||
 | 1st gen 5 oz | ||
| 1st gen 10 oz | |||
| 1st gen 25 oz (exists?) | |||
| 1st gen 50 oz | |||
| 1st gen 100 oz | |||
| 2nd gen 1/2 oz | |||
| 2nd gen 1 oz | |||
| 2nd gen 2 oz | |||
| 2nd gen 3 oz | |||
| 2st gen 5 oz | |||
 | 2st gen 5 oz double hallmark | ||
| 2nd gen 25 oz single hallmark | |||
| 2nd gen 25 oz double hallmark | |||
| 2nd gen 50 oz | |||
| 2nd gen 100 oz (exists?) |