Mineral oil is not a popular choice in the soaping community, here is some info.:
Material Safety Data Sheet for Mineral Oil
Toxicology – may be harmful by inhalation, ingestion and through skin absorption. Irritant.
The British Institute for Allergy & Environmental Therapy: Mineral Oil Petroleum Derivative on Beauty Products by Kit Anderson
Mineral oil (classed as a petrochemical pollutant and xenohormone) can have negative effects on hormones and the skin’s ability to breathe, attract moisture and detoxify. It can also slow down cell renewal and be the second (after the sun) most likely cause of premature ageing. In fact sun screens produced from mineral oil may promote skin cancer as well as colon and breast cancer. However, no cosmetic manufacturers put health warnings on their products and in the US, the FDA does not require this information to be on packaging.
Is Mineral Oil a Safe Lubricant?
Mineral oil does not make a good lubricant. Anything with oil in it, such as petroleum jelly, baby oil, bath oil, and hand lotion, massage oil, etc. are all rather unsafe because they block pores and do not allow the skin to breath [sic] and trap bacteria which can then multiply, which may lead to infections. Oils are also bad for condoms and toys since they deteriorate break down latex. Some women seem to be able to get away with using very pure oils, such as olive or almond oils if they are not using toys or latex, but many of us will end up with infections as a result.