The 1854 "Mining Magazine" article shown below indicates that there was a pair of coke ovens in Barrelville, Maryland, stating: "The failure of the Parker Vein Company has suspended certain very interesting experiments in a new process of burning coke. A short time since, M. Guillaume Lambert, agent of the Belgian government, visited the Cumberland region, and induced the Parker Vein Company to try his improvement in coke ovens. The ovens were constructed at Barrelville; but the explosion of the Company has prevented a fair trial of their efficiency. M. Lambert's invention consists in constructing the ovens two by two, so that the smoke and gaseous products generated in one of the earlier stages of the coking process may be burned in the other which was charged earlier, and in which the coking has progressed to a more advanced stage, and may deposit therein a portion of their carbon. Thus the incombustible products, by passing in contact with the exterior of the oven in which the process is least advanced, serve to assist in heating the charge and setting free the gases. Another part of the invention consists in certain means by which each or any one of a long range of ovens may be discharged of its contents at once."
