This token was an instrument of control used by the slave owner at the Morro Velho mine in Brazil, a British owned company long after Britain had abolished slavery in its own territories. It appropriates imagery used by abolitionists. I wish the seller or buyer would entrust this object to a museum willing to display it and put its function into context. It is only the second such specimen which I know of (do you know of more?! please let me know!), neither is in a public collection.
Here is an excerpt on this medal from a forthcoming article of mine (I also have an earlier post on this topic). I’ll obviously have to correct the footnote prior to publication:
Nearly the same imagery was adopted in a most disturbing manner by a notorious British slave owning company in Brazil, the Morro Velho gold mine, a mine still in operation today. In a firsthand account, Captain Burton praises the use of these medals and their role in a fortnightly inspection of all the slaves, working on the theme of how much better life is for the slaves than it used to be, and how much better off they are than their un-enslaved kinsmen (1869: 236-7). The silver medals, commissioned from London, had been introduced into the ceremonies in 1852 and seem to have been awarded to those with five years ‘good conduct’ to mark their approaching freedom (Childs 2002: 51). Seven years of such continuous ‘good conduct’ are said to have led to emancipation, although the mining company never chose to define what constituted ‘good conduct’, leaving the judgment inherently arbitrary (Childs 2002: 44). Thus the abolitionist message of freedom is substituted for an illusory promise of possible freedom and the medal, like the social ritual of the muster and the uniforms, becomes part of the means of control. It also imitates the practice of the abolitionists who had made a fashion out of wearing such medallions to advertise their own political sentiments; notice the marks left by a clip visible at the top of the illustrated medal. Here the palm tree is used to identify the man as African and thus his status of one not yet liberated, or, if liberated, only having achieved such a state by the agency of a European power.
 I only know of one surviving specimen, which was sold by Baldwin’s Auctions Ltd, Auction 65, lot 1131 (4 May 2010); it was not possible to secure permission to illustrate this specimen, but an archived image can be found here: <https://www.acsearch.info/search.html?id=780251>. The auction catalogue entry reads, in part: “A note with the medal states, “Morro Velho slave medal of Freedom … given by dying slave to a missionary. Given to me by an Old Lady as a parting gift when leaving Chiswick”. The image of the slave derived, perhaps, from C F Carter’s 1834 medal to commemorate the Abolition of Slavery. Viscondessa de Cavalcanti’s Catalogo das Medalhas Brazileiras, lists the medal under “Abolition of slavery” and attributes it to 1848. She also quotes “Sr Hopkin, president of the company in 1888” who said that by 1882 all but 28 had been emancipated. Morro Velho is a complex of gold mines located near the city of Nova Lima in the Minas Gerais state of Brazil; in operation since 1835, it is the world’s oldest continuously worked mine.”