Table 1 Descriptive statistics for reserve/production ratio data for a selected range of commodities^27,28,29 from 1956 to 2018 and from 1987 to 2018 (with continuous data available for the latter period).

From: Future availability of non-renewable metal resources and the influence of environmental, social, and governance conflicts on metal production

Commodity	All data					1987–2018
Commodity	Slope	R2	Mean	STDEV	Trend	Slope	R2	Mean	STDEV	Trend
Antimony	−0.97	−0.76	36.9	24.1	Null	−1.97	−0.84	26.2	21.9	D
Bauxite	−0.72	−0.25	168	57.3	Null	−4.80	−0.97	159	46.6	D
Bismuth	0.62	0.66	32.7	16.2	Null	0.41	0.25	38.6	14.5	Null
Cadmium	−0.17	−0.26	31.6	11.9	Null	−0.01	−0.03	27.8	2.98	Null
Chromium	−33.2	−0.90	790	659	D	−19.8	−0.52	349	322	D
Cobalt	0.03	0.01	117	41.9	Null	−3.14	−0.69	125	42.5	D
Copper	−0.27	−0.52	40.5	10.1	Null	0.14	0.27	34.3	4.83	Null
Gold	−0.22	−0.80	21.8	5.05	Null	−0.12	−0.61	19.0	1.85	Null
Ilmenite	−2.89	−0.51	143	111	D	2.55	0.80	85.7	29.7	I
Indium	−0.88	−0.89	16.9	10.5	Null	−0.70	−0.69	12.3	6.28	Null
Iron Ore	−3.36	−0.68	184	96.8	D	−3.48	−0.94	123	34.7	D
Lead	−0.07	−0.19	22.2	6.8	Null	−0.15	−0.67	20.4	2.05	Null
Lithium	4.08	0.28	292	107	I	4.08	0.28	292	107	I
Manganese	−5.22	−0.55	138	170	D	−2.74	−0.86	65.8	29.9	D
Molybdenum	−0.46	−0.42	54.7	21.0	Null	−0.02	−0.03	47.1	8.03	Null
Nickel	−1.81	−0.81	70.0	43.9	D	−0.55	−0.71	42.2	7.25	Null
Phosphate	−12.9	−0.69	358	362	D	7.90	0.79	152	94.4	I
PGE	2.18	0.71	131	59.6	I	−2.33	−0.84	170	26.1	D
Rare earths	10.0	0.28	977	488	I	−21.1	−0.48	1123	409	D
Rhenium	−9.84	−0.76	131	165	D	−1.71	−0.82	68.7	19.7	D
Rutile	0.48	0.11	97.9	82.3	Null	−3.76	−0.73	109.2	48.5	D
Silver	0.01	0.05	17.7	3.48	Null	0.10	0.30	17.7	3.08	Null
Tantalum	−0.99	−0.31	76.8	42.9	Null	1.47	0.41	64.6	33.5	I
Tellurium	−5.08	−0.70	216	92.0	D	−7.07	−0.82	196	77.2	D
Tin	−0.13	−0.31	26.6	8.50	Null	−0.54	−0.67	24.9	7.55	Null
Tungsten	−0.54	−0.66	56.5	16.0	Null	−0.69	−0.70	49.7	9.25	Null
Vanadium	−1.66	−0.33	248	73.0	D	0.06	0.01	231	64.7	Null
Zinc	−0.06	−0.42	21.0	2.98	Null	−0.13	−0.48	20.2	2.53	Null
Zirconium	−1.68	−0.73	67.8	44.3	D	0.13	0.11	43.2	10.9	Null

“Slope” indicates the slope of the least-squares best fit line for the data in question, R2 indicates the correlation coefficient between reserve/production data and time. STDEV or standard deviation documents the variation in the data, and “Trend” indicates the overall trend of the slope of the reserve/production ratio best fit line over time, with I = slope increasing by >1, D = slope decreasing by < −1, and Null = change of either <1 or > −1.

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Table 1 Descriptive statistics for reserve/production ratio data for a selected range of commodities^27,28,29 from 1956 to 2018 and from 1987 to 2018 (with continuous data available for the latter period).

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